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Shortwave Mineral Light Review - (Portable Lights)

Update June 2019 - This review was written over three years ago (2016).  At the time I tried to present technical "facts" so that users could make up their own minds.  My thought was that the manufacturers in our little hobby could not be upset if I just presented facts (I was wrong!). And really, it was a cop-out on my part, making the review more complex than needed (the original review is below this summary for those interested).  Users need (and want) to know what light I think best - so here goes; keep in mind this is my own opinion, as unbiased as I can keep it.


Presented below (as of June 2019) is a quick summary of each light, starting with my favorite and working down:

#1 - Engenious Design's DRK Light 

This is the newest entry into our hobby, and as such the designers were able to take advantage of the latest technology.  This light is 2x to 4x the UVC output of any comparably priced light. They have a wide range of lights and LED solutions: 


-Highest UVC (shortwave) power of all reviewed for the price

-Integral lightweight battery w/ voltage monitoring, w/-Battery charger

-Off the shelf replacement bulbs, buy from any lighting distributor

-Other solutions offered for MW, LW LEDs

-Fan cooling


-Can't think of any

#2 - UV Systems SuperBright   

The SuperBright is the workhorse of our hobby.  It's been around since forever and has perhaps the widest following.  Reliable, bright, and well-engineered - if you're looking for a bright mid-power light (less than half the brightness of the light above), reliable, and a solid reputation, this light might be for you:


-Built like a tank, perhaps the most reliable (of those that have a history)

-High UVC output

-Tremendous reputation, been around the longest

-Other solutions offered for MW and LW, large display lights


-Most expensive of all lights tested

-Single battery choice, add'l cost, expensive and cumbersome lead/acid

-Custom bulb (pricey replacement bulbs)

-UVC output degrades with heat (no fan)

-Actual specifications for UVC power not revealed (and can't be found, custom bulb)

#3 - Way Too Cool 9-Watt 

WTC has sold lights for many years and has a reputation for low-cost, entry level lights, as well as multiple wavelength lights and high-end lights.  The light reviewed here is the cheapest of the four in this review; they offer others that have higher power output (but about half the Engenious Designs light for a similarly priced light):


-Lowest price (but also lowest UVC output).  Other models might compare in power and price

-Fan cooling

-Huge lineup of lights, SW/MW/LW lights (combos) available in other models, higher power,  large display lights

-Great service, regional distributors always willing to help, offer options


-Modified off-the-shelf bulb (but not hard to modify)

-Packaging not very rugged

-No battery option (relies on distributors)

#4 - UV Tools M18 -

UV Tools sells a low-cost entry level light for beginners.  AT $55 to $125, it's a great way to see if this hobby is for you.  But if you get serious you will quickly find yourself looking to purchase one of the other lights.  I reviewed their 18 watt model here, as the little model simply does not fit with the lights in this review (in hindsight I should have reviewed the little light).  Not even sure they offer the model reviewed here anymore.


-Offers a really inexpensive low-end light (not reviewed here).  They appear to focus on low-end, beginner lights

-Other solutions offered (I think) for large display lights


-I really can't recommend the light reviewed here for a host of reasons

-Uses inferior UV bandpass filter (degrades 50% in 100 hours)

-Not sure what their current plans are for higher end lighting

-Web page presently doesn't show stock for anything other than their little light

It should be noted that there is a lighting manufacturer in Europe (finally).  I have not reviewed the light but it is very similar in design to the top choice above.

There are several other portable lights available (Raytech, Spectroline, for example) but they really are not serious contenders IMHO for a good mineral light so I did not include them in the review.

Note: all manufacturers reviewed here have been given the opportunity to comment.  Only one has - UV Systems.  Those comments can be found at the end of this review.

Below is my original review from 2016.  Be warned, techy and probably boring.


Maybe some definitions will help a little:

BULB - the "tube", the actual lightbulb.

LIGHT - refers to the entire "box", filter, fans, and bulb.

By M. Cole, MinerShop - 12/10/16 (updated Feb 2018)

There are three types of mineral lights commonly used in our hobby: longwave, midwave, and shortwave. Some lights have only one wavelength (shortwave usually), others have all three.  Shortwave lights are reviewed here as they are the most popular light used by serious enthusiasts.  If you are not familiar with UV and UV lights you can learn more under the UV Topics pages.

Choosing a shortwave mineral light is difficult. Specifications used to promote many of the lights on the market are misleading and inaccurate, quoting the overall power used to light the bulb, not the much lower power of the UV generated by the bulb (which is all we care about).  Worse, some manufacturers don't disclose any details about critical components (filters or bulbs) in their lights.  How does the buyer make an informed decision?  Imagine buying a car without knowing the horsepower of the engine, a lightbulb without knowing the actual watts, a powerful flashlight without knowing the lumens, etc.


These pages will provide some insight to selecting a light (among those on the market as of Dec 2016, updated Feb 2018 to include a significant entry to the market). Only three lights were tested but the results can likely be applied across product lines; each manufacturer uses similar components to build their lights; some have more power and wavelengths, and of course different efficiencies in their designs.

There are a limited number of companies making mineral lights today.  Of these I only consider a few of them to be serious about our hobby; others are marketing lights designed over 20 years ago, or lights that are simply too underpowered to be of any use.  Of course as time goes others will join this list (I hope).  Be sure to check the list of all manufacturers for the latest suppliers. 

Since this review was done, two new companies have entered the market.  Both lights are very similar.  Check out their products:

Why am I qualified to do this?

Some will probably say I am not; they may be right. I am an "out-to-pasture" electronic engineer, a passionate fluorescent mineral hobbyist, and I have built my share of lights for my own use and for friends.  I host a set of DIY pages on my web site and thouroughly enjoy the technical aspects of our hobby.

I don't sell portable SW lights and don't plan to.  I have no business connections with any of the manufacturers listed here.  I consider them my friends (and hope they still will be after posting this review).

All measurements are approximate and will vary depending on components, temperature, solarization, and the phase of the moon. Opinions expressed are my own.

Testing all models of lights is not in the scope (or limited budget) of this review.  I chose the lowest cost, serious, portable entry-level light from three manufacturers offering competitive products as of late 2016, and purchased one from each.  A fourth manufacturer entered the market in 2017 and I included specs for that light in Feb 2018. I conducted a detailed review, tore each apart to gauge the design and quality, and ran tests to verify the UV outputs.  Other manufacturers may release new offerings in the future which should be included here (and might be someday). I monitored the progress of the 4th light as it was being designed and am very familiar with the inner workings; I have not done "hands-on" testing with the 4th light.

Bypass all the techy stuff below and "JUMP TO THE CONCLUSION?" 
Click here...

Shortwave (UVC)

"U/H" Bulbs

Average UVC Watts Out

UVC watts table
What's a WATT got to do with it?

A "Watt" is a unit of power.  In the case of our lights, wattage is most often incorrectly used to imply UV light output.  This can easily be misinterpreted.  In some cases, information about bulb wattage and UV light output is not provided.

There are three power (wattage) measurements that matter in our lights: UVC (shortwave) wattage, bulb wattage (relatively unimportant), and light wattage (the whole shebang).  The one that really matters when describing the UV output of a light is the UVC wattage.  Every bulb has a detailed specification that states its UVC watts and all manufacturers know this data.  This number is a fraction of the overall power of the bulb (bulb wattage).  For example, a standard 9 watt Philips UVC PL-L bulb consumes 9 watts of power to light and only produces 2.3 watts of UVC.  

The overall wattage of the bulb is the least important power rating, yet most manufacturers state that number and the consumer can easily misinterpret it as the UV output of the light.  In fact, models are often named based on this wattage number - "9 Watt DC", "18 Watt Field Lamp", etc.  One manufacturer simply doesn't provide any wattage information about the bulb used.  Without the proper data (UVC output) the buyer cannot make valid comparisons.

The third measure of power is the wattage consumed by the entire light, the fan, LEDs, etc.  This is the amount of power it takes to light the bulb and drive the internal electronics (mostly the ballast/driver for the bulb).  This will always be higher than the wattage of the bulb and is a determining factor in battery usage.

It's somewhat surprising how little UVC is required to make our minerals fluoresce.   The table to the left gives UVC output for common "U"-tube (or "H") bulbs used in the lights for our hobby.  (just an example. Certain brands may vary slightly, as well as quartz bulbs vs. soft glass - but they are all within +/- 10%.)

Just the facts, please?:  The table lists the potential absolute maximum shortwave (UVC) wattage of the light OUT OF the UV bandpass filter. This number is a fair comparison, and is easily computed by the manufacturers based on the specifications of the components they use - the lamp's UVC watts and the filter's transmission characteristics.


The resulting number would be a best case UVC power output of the light - in a perfect world (which is never perfect).  It is not an accurate measurement, but an "absolute max" spec.  There are many other factors which affect this output (such as reflectors, heat, efficient electronics, solarization, component tolerances, etc).  But at least it's a starting point where the average consumer can try to make an intelligent decision.  Not kidding myself, but wouldn't it be great if power output was "just the facts"?  Comparisons would be so much simpler.

In the table I used  shortwave UVC output, after the filter, as the overriding factor in this mineral light review - the more UVC watts, the brighter the light (usually).  The table summarizes the results of my testing and analysis.  Below that is detail, by light, of my findings.

Table of Test Results (02/24/18)

I welcome "factual" comments from the manufacturers on this data and will publish any commentary which proves a different result.
(All measurements @12vdc, room ambient)  
I had to make a couple of "knowledgeable assumptions" (ballast efficiency, bulbs, and filter types) because the manufacturers do not provide this data.  If I am wrong the manufacturer can provide the correct data and I will revise accordingly.

View Hoya U-325c vs. ZWB3 Transmission Graph

Technical Summaries
UVC (Shortwave UV) Output

UV Systems
SuperBright 3

The Superbright 3 uses a proprietary, custom shortwave (UVC) bulb and a Hoya filter - the standard filter type in our hobby.  They do not disclose the power of their bulb, but my research indicates it is rated at 17 watts, and is slightly underdriven @15.3 watts. This combination results in a theoretical UVC output  - 3.5 watts cold.  It suffers about a 20% loss in output when hot, reducing this to 2.8 watts.

Note: My numbers are based on my own research and measurements.

UV Tools
"18 Watt" model

UV Tools "18 watt" model has a standard (off-brand) 18 watt shortwave bulb and uses a ZWB3 type UV filter (or equivalent) with lower UVC transmission than Hoya.  This results in only 2.4 watts out when cold even though it uses a relatively powerful bulb.  Due to a lack of cooling, it is reduced by 20% to 1.9 watts when hot (after 10 minutes, more beyond 10 minutes).  

Note: The type of filter used is not disclosed by the manufacturer, as well as transmission and solarization data. My numbers are based on my own research and measurements.

Way Too Cool

"9 Watt" model

The Way Too Cool light uses a modified Philips 9 watt shortwave PL-L bulb and appears to be overdriven to 13w (+/-1W).  Combined with a Hoya filter, this results in a respectable 2.1 watts from such a small bulb, cold.  


Since it is fan-cooled there is very little loss in output from heat over time.  

Note: Overdriving a bulb is destructive and will result in a shorter bulb life. I'm OK with this - would rather have bright UV than longlife bulbs (they're cheap)

Engenious Designs

DRK Light

The DRK Light is a fully portable unit that uses a Hoya filter and an off the shelf 35W Philips shortwave bulb generating 9.75 watts of UVC output - the highest of all the lights in this review. Along with the standard attributes you should expect from a UV lamp, the DRK Light also features a built in battery voltage monitor, ruggedized features, and active cooling for both the bulb and the ballast.


Since it is fan-cooled there is very little loss in output from heat over time. 

Filters and Reflectors

Quick note on filters:  Hoya U-325C filter glass is the standard for our hobby.  Testing has proven it to have the best transmission characteristics @254nm (shortwave), pass the least amount of visible light, and has the lowest solarization rate of any filter on the market.  In recent years several sources for the ZWB3 filter have appeared from China.  Originally an Optima glass, ZWB3 is roughly equivalent to Hoya U-330 midwave glass; it's not really a SW glass.  I am not aware of any testing on this filter for our hobby and the Chinese manufacturers of the glass do not provide solarization data.  Stated transmission at 254nm is roughly 38% to 42%, while Hoya is ~68% to 70%.  Obviously this can be compensated by simply using a higher power bulb but that creates a whole set of other issues.  

The graph shows Hoya transmission compared to ZWB3.  Click for a larger chart.

Hoya vs. ZWB3

Hoya vs. ZWB3

Why use anything other than Hoya? - Cost.  ZWB3 glass is about 1/8th the price of Hoya glass.  The filter is the most expensive component in a light; save $$$ here and the light is cheaper (to make, at least).



When I first wrote this review there was no solarization data available comparing Hoya filters to ZWB3 filters (the two currently used in the lights built for our hobby).  One of the members of the Fluorescent Mineral Group on FB got a copy of a graph showing test data - graph produced by Hoya.

As can be seen from the graph, ZWB3-1 solarizes almost 50% in the first 100 hours (ZWB3-2 is even worse but I can't imagine anyone using that).

A quality lamp will only use Hoya.  There might be justification to use ZWB glass (cost) but the buyer should be aware that after 100 hours the amount of UVC output by the light will be drastically reduced.  But for occasional use, and as a "first light" to discover if this hobby is for you, a light based on this filter might be a reasonable choice.  But you will eventually buy a real lamp.

Hoya U325c vs ZWB3 Solarization

The SuperBright has a large 62 sq cm Hoya filter window,  and the visible light fills the window showing the efficiency of the reflector (all filters allow a little visible light to escape, making these photos of the filter window possible with a time exposure) .  


A large window area combined with an efficient reflector results in more UVC output.

There is no protection for the very expensive filter glass, but one can be rigged rather easily. The best method I've seen with these lights is a dome of chicken wire attached under the rubber feet.

The filter is easily replaced when the time comes (and it will - metal, glass, and rocks just don't mix).  Perhaps 50% of the SuperBrights I've seen in the field over the years have their filter broken or cracked. 

UV Tools "18 watt" model appears to use a ZWB3 filter (or equivalent - exact type not disclosed) with lower UVC transmission compared to Hoya.  Solarization data is not available for this filter; I have contacted the manufacturers of the ZWB3 material and they do not have it (see conclusion at the end for more on solarization).  (Solarization is damage caused by UVC over time, reducing transmission significantly).  

Filter area is 72 sq cm but not fully utilized in the lamp I tested.  The UV bulb was mounted off-center such that 25% of it is not even visible in the window, and the filter does not extend the length of the bulb.  The reflector is an inefficient flat metal piece.

Quality control issues are of concern.  Not only is the bulb not centered on the window, a visibly sloppy "glue job" mounting the filter further shows a lack of attention to details.

No protection is offered for the very delicate filter window (only 2mm thick, mounted on thin plastic, vs 4.5mm for Hoya).  I don't see an obvious way of mounting one.

The Way Too Cool light has the smallest filter area of the three (49 sq cm).  The light fills the Hoya window very nicely with help from the internal reflector.

A metal guard protects the middle area of the expensive filter but offers minimal protection. It is placed directly next to the filter glass and will do little to protect the glass when the light is used to break a fall (which will happen one day).   The plastic case might help a little as it has some "give" allowing it to bend instead of just cracking the glass.

The DRK Light has the largest filter area of the four (62 sq cm).  The light fills the Hoya window very nicely with help from the internal reflector.

Two metal guards protect the expensive filter but offer minimal protection. Like WTC, they are placed directly next to the filter glass and will do little to protect the glass when the light is used to break a fall (which will happen one day).   

The SuperBright obviously has an excellent reflector/filter window combination, as does the DRK Light.  The large windows allow the reflector to efficiently reflect the UVC from the back of the bulb as can be seen in the window shots above.  Reflector material and design is a critical component of light design and should not be dismissed. The WTC window is just wide enough to allow light out of the front of the bulb; much of the light at the rear is lost.  The UVT reflector/window is not efficient.

Beam Spread and Pattern

Note: This test only shows the three lights initially tested in 2016.

This is an attempt to visualize the pattern and intensity of the UV light generated by each light.  UV sensitive beads react to the intensity of the light and change color (they all start out white, and darken based on the intensity of the UV).  

Each light was positioned directly above the 4' x 2' platform at exactly the same distance (12") and location. The beads were exposed for ten minutes and photographed at the end of the exposure.  The darker the beads, the more intense the UV.

The beads were faded completely before the next test was started.

(Click for larger image)

The most intense color is observed after exposure by the UV Systems light.  Note how the intensity is strongest in the middle but reaches all the way to the edges.  Note the spread of the light held 12" above the beads - this is the beam spread.

The UV Tools light shows the next level of intensity but does not present an even beam; the right side falls off sharply due to the misalignment of the bulb to the window (see filters/reflectors above).

The Way Too Cool light shows an even distribution of power, slightly less than both of the other lights. This is attributed to a smaller filter and lower power bulb.

I would expect the DRK Light to come out on top in this test due to its power and large window area.

All three of these lights will initially (before solarization sets in) do an adequate job lighting up our mineral specimens in the field.  Typically we find ourselves hunched over with the light a foot off the ground in the twilight hours, or huddled under a BBQ grill cover with the specimen held right up against the light.  In the real world, rarely will you be using your light to scour grounds on a moonless night from waist level; you would miss too much, or break a leg navigating mine dumps at night.  I am personally less concerned about the "throw" or beam spread as most often I find myself examining a rock held a few inches away from the light.  Home display lights may be a little different, requiring a focused beam spread.  Few people have the luxury of scouring the Franklin Buckwheat dump on a moonless night.

Heat / Bulb Temperature

Fluorescent bulbs are very sensitive to temperature.  Most reach maximum brightness around 104f, taking a couple of minutes to warm up to that temperature.  Usually they stabilize at their optimum temperature when installed in open, air cooled fixtures. Output will fluctuate slightly with the ambient temperature of the room. Our lights, by necessity, are closed systems; the heat is trapped and the bulb continues to heat up.  As they heat the UVC output drops, perhaps by 20% to 30%.  Worse, our bulbs all produce a little ozone which blocks UVC (think ozone layer). It is also trapped in the light and potentially can reduce some of the output.  Active cooling is helpful. (Graph shows heat build-up measured in the UV Systems light - uW/sq cm)

UV Systems heat graph

UV Systems

The SuperBright, like all our lights, is a closed (sealed) box; very little heat can escape and heatsinking is minimal.  The instruction manual explains how heat can affect the UVC output, and recommends using the light for ten minutes, then turning it off, allowing it to cool for 45 seconds for maximum UVC.  This is not real world usage; nobody has a stopwatch in the field.

The graph shows the effect of heat (and possible ozone) buildup on the UVC output - approximately a 20% reduction over time. Allowing it to cool per the instructions only improved the output by 10%, and it quickly dropped back to 20% after a minute or so of use.  Adding a fan helped greatly  (see below).

UV Tools

UV Tools has the same problem as the UV Systems light.  Heat buildup in this light is even worse due to the high power bulb, seeing a degradation in output as much as 20% in ten minutes, 40% after 1/2 hour.

Since the light is an AC powered light I could not install a DC fan to test, and I am not aware of any AC fans that are small enough to fit in the light's housing.

Way Too Cool

Way Too Cool offers active cooling. A fan is standard on their light and can be turned off by a switch.  I did not see a significant change in output due to heat buildup beyond what is expected from the bulbs under normal operating temperatures.

At first I wondered why bother with a switch? A buddy pointed out that it's nice to be able to turn it off when taking photographs.  Even the minor vibrations from a fan can cause "soft photos" when taking time-exposures.

Engenious Design

Engenious Designs offers active cooling.  A fan is standard on their light.  I would not expect a significant change in output due to heat buildup beyond what is expected from the bulbs under normal operating temperatures.

Active cooling helps significantly.  I temporarily installed a small (30mm) 3cfm DC fan on the UV Systems SuperBright and ran the test again - a huge improvement.  I bet a little stronger fan (6cfm?) would show even better results (but you don't want to cool it too much; the bulb needs to run hot for maximum output). (A fan is easily installed by drilling a 30mm hole with a step drill and just connecting the 12vdc power to the on/off switch (very low current draw - around 80ma).  Be sure to check with the manufacturer before you void any warranties.)

Power and Battery Requirements

UV Systems

As tested the SuperBright draws 1.42A on average from a 12vdc battery.  The lamp remained lit down to 8.5v, but with greatly reduced output.

A universal (100-220) AC to DC power supply is shipped with the base light.  An optional lead/acid battery may be purchased separately; UV Systems claims it will power the light for about  seven hours.  I did not test this, but I believe a more realistic capacity is four to five hours.  After that the battery will likely be discharged to 10.5vdc and light output will be very dim.  Worse, you run the risk of damaging the battery.

An optional battery cable is offered allowing you to connect to your own battery of choice via a cigarette lighter connector.  I recommend LiFE battery packs - far superior to lead/acid (

UV Tools

The UVT light is a 110vac light.  Plug it into any AC outlet and you're good to go.  But for field use you must purchase a DC to AC inverter, hooked up to a battery.

This requires another piece of equipment in the field, and puts additional drain on the battery.  As tested, this light draws almost 2A @12vdc.  

Per the manufacturer, their external battery/inverter combo offers "a evening's worth of field collecting".  Probably accurate, and with the low-voltage detect of the inverter, the light will shut down when the battery reaches 10.5vdc (almost all inverters have this battery saving cutoff standard).

Way Too Cool

The WTC light comes ready to be plugged into any battery that has a cigarette lighter connector.   The total current draw (including the fan) is around 1.25A.  Like UV Sys, there is no automatic shutdown and the light will drain a battery if allowed (very bad for the battery).

A separate AC to DC power supply may easily be adapted to power the lamp, but I can't find one offered on their web site.

Many different battery options are offered by the distributors that carry the Way Too Cool line of products.  WTC does not offer a battery on their web site.

Engenious Designs

Unique among the lights reviewed, Engenious Designs includes , in the base price, an integral battery with their DRK Light.   Attached to the light, it only adds 7 ozs (very well balanced) and will last for approximately one hour.   A spare battery is easily connected for longer usage.  This eliminates the battery umbilical cord - a major step forward.

The supplied batteries (included in the base price) have voltage protection so the packs won't be discharged beyond 11.0 volts.

An optional wall power supply is available to run off household AC.

Summary and Conclusions

The proof is in the pudding.  I selected a piece of tugtupite that had some white and pink color (easiest to photograph accurately) and some light blue chkalovite.  I positioned each lamp at the same spot in front of the rock, used the exact same camera exposure settings and allowed each light to warm up for 5 minutes before taking the pic.  This animation shows the differences in brightness between each light - a silly UVC watt really matters. (Note: all UV Tools tests were completed before the filter became solarized.)



Overall I found each light would be satisfactory for field use, able to light up a reasonable area on a dark night.  In terms of brightness, one of the most important factors, the UV Systems light excelled with an even throw and intensity.  I believe the DRK Light from Engenious Designs would easily match or beat any of these lights in a brightness shoot-out simply due to bulb power and filter window area.  The Way Too Cool light was initially the least bright of the three (but moved up late in the race).  It was also the least expensive - and the company offers a diverse line of products which, for a few $$$ more, will surpass some of the other offerings.  The UV Tools light, by using a high power bulb, was able to initially overcome the inferior UVC transmission rate of the non-Hoya filter glass (but "faded" late in the race due to solarization issues).  Although the Engenious Design light was not included with these actual hands-on tests, I am confident that it would have come in #1 on this test.  It uses Hoya glass along with a 35W bulb - resulting in more than twice the UVC output of the brightest light actually tested.

But we do not live by brightness alone.  There are other factors which should be considered when buying a light.  These are summarized below:

The SuperBright is built like a tank.

Lightweight but solid, very professionally assembled.  A custom aluminum case, along with a powerful custom bulb, well-engineered reflector, and efficient bulb driver (ballast) results in a light which will last many years in the field.  (The bulb is driven at a conservative 15.2W @12vdc. At 13.2vdc it is driven at its rated wattage of 17W.)

The SuperBright is the most expensive field light in its class.  Custom bulbs and cases aren't cheap to make.  But if you're looking for a light that can take abuse, puts out the UV, and you can afford the extra $$$ that quality demands, this is the light for you.

A quick note on power cords: The SuperBright has an input connector allowing the cord/cable to be easily replaced.  The other two lights have permanent cords with simple strain reliefs. They will break over time with flexing. (Didn't have any other place to put this. Superflex wires would address this.)

Like all of the companies in this review, UV Systems is essentially a one-man technology show. 

To be aware:

  • The bulb is a custom, single source component and may only be purchased through UV Systems.

  • Cost - some might say the light is overengineered.  You pay for the "tank".

  • Limited battery options.

  • Switching between SW, MW, and LW requires installing a new bulb.

  • UVC output degrades up to 20% with heat.

UV Tools seems more focused on their little "AA" and "D-cell" powered lights which address the low-end of the market.  I have not tested those lights as I consider them too low power for use as a field light, but I can imagine it as a great way for newbies to try out the hobby without investing hundreds of $$$ in a light.

The entry level shortwave light tested here exhibited quality control issues.  It seems to have the power initially to compete in this segment of the market but the use of a non-Hoya filter concerned me greatly.  As of this writing there is no data on the solarization of this filter.  The manufacturer does not provide the specs of the filter, or what type it is.

This just in:  I decided not to sell this light and instead run some solarization tests.   After 48 hours the filter showed approximately 35% solarization.  This means that the shortwave (UVC) output has been now cut to 65% of the numbers reported in this review.   After 100 hours the rate has slowed, but the damage has been done. (More about solarization) - See discussion above for more about filters and solarization.

  • Heat causes a 20% to 40% reduction in output, depending on time

  • Inverter req'd for field use

  • Q/C issues

  • Filter solarized 35% in 48 hours, 41% in one week

  • No options for MW or LW


Company management has stated that their priority is the small "AA/D-cell" powered lights they sell.  They see them as good entry level lights for new hobbyists.

Way Too Cool

Way Too Cool offers a huge lineup of lights - some might say too many.  There's an advantage to picking a few models and getting really good at building them.  But if you're looking for a specific combination, you will likely find it at WTC.

The packaging is average to poor.  WTC focuses on offering an affordable product.  This means plastic instead of metal and other cost-saving measures.  The bulb they use is off-the-shelf with a minor modification.  It is overdriven hard which will result in shortened lamp life (but I'm ok with that - brighter the better, and replacement bulbs are only $40 - <$15 if you roll your own).

Although WTC came in at the bottom of the list in brightness, they were at the bottom in price too (but after heat/solarization tests they moved up a little).  They also sell higher power, higher cost, portable lights (many versions, including multi-wavelength lights).  These lights will be very similar to the one reviewed here, just much more "oomph". 

Like the others, essentially a one-man technology show...

  • Lowest initial output of the three tested, but after heating and solarization issues w/ the UV Tools light, it takes 3rd position

  • Plastic case

  • Off-the-shelf bulb requires modification

  • SW/MW/LW lights (combos) available in other models

  • Shortened bulb life

  • No AC operation (must buy optional AC adapter, none listed on their website)

Their DRK Light is the newest entry into our UV market, and adapts some of the newest technologies.  This light is my personal choice for a field light.  

The packaging is excellent - metal with filter protection, professionally assembled, and provides the highest UVC output of any light (more than twice the nearest competitor).

It is priced competitively and the pricing includes an integral battery as part of the package (unique).  

Like the others, essentially a one-man technology show...

  • Highest UVC output

  • Integral battery with voltage monitoring display

  • Battery charger included, extra quick-swap spare batteries available

  • Off the shelf bulb standard

  • Presently no MW option offered

  • LW - LED solutions offered

Their website offers other UV products, including home display lights and high-power LED solutions.

All of these companies offer a complete product line, ranging from the small portable lights reviewed here, to large, multi-watt display lights (I refuse to state bulb wattage - remember, it's the UVC wattage that matters).  You can view the rest of each company's product line on their web sites, details here.  
Still have questions?  Perhaps our FAQ will help.

"An informed buyer is an "enlightened" buyer.  Insist on knowing what you are buying"

Comments from Manufacturers


UV Systems


  • Claims that their ballast operating at 23khz is unique.  It is not.  The ballast is an electronic ballast, analog magnetic, commonly used by most mfgs of 12VDC lights.  It offers no advantage except perhaps for efficiencies, but I have no way to tell what that is (easily).  

  • Wattage of the tube/bulb used - Not sure what the claim is here other than the fact that they (the manufacturer) claim to not know the wattage of the tube they are using, so how could I know it?  I had to make an educated evaluation, as noted in the caption of the table, because they do not release this data (not hard, just current and voltage measurements).  ALL major tube/bulb manufacturers (that I am aware of) provide this data.  If they provide this data I will include it.

  • Claims a large difference in overall power to the light (my measurements compared to theirs) - my feeling is that they are measuring the AC power supply and the light together.  That is not the correct way to measure the power of the light alone (important for battery considerations).

  • Operating time of their lead acid battery - my review states that it is much less than claimed by the manufacturer. I am correct, they are wrong (just no other way to say it).  Simply put - they sell an 8AH battery.  At 12VDC = 96 watt hours (8A X 12V).  Using the actual measurement of 17 watts power consumed by the light, this results in 5.64 hours of runtime (96 divided by 17).  Google "depth of discharge" for more information.

  • Overall Claim - A Light's Power is determined by the package (tube, reflector, ballast).   I agree.  But we have to have a starting point and UV Systems cannot/will not provide one.  Without knowing the wattage of the custom tubes they use the only other way to compare lights is to measure each in a lab with calibrated equipment.  Nobody is going to do that, so computing the wattage of their tube is the best we have.

Mfg Comments
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