I purchased the BLUE version of this flashlight as a curiosity some time back - and it's one of the most interesting lights I have. The device is lightweight and VERY small. The Blue beam is extremely saturated without any need for an internal color filter. The light DOES trigger fluorescence in some subjects but not others. For example, certain fluorescent paints and markers will glow but not others. Sodalite mineral specimens don't react to this frequency of light yet other items do. The projected beam is lensed in a unique manner (due to the TIR lens) that keeps the beam tight, similar to the output from an LEP flashlight. And the saturated blue light is eerie to see, almost other-worldly in appearance when painting the side of a water tower or a building. The hot-spot remains tight, even over a good distance, though not quite as tight as an LEP flashlight. The Hot-Spot is barely 8 inches wide at a little over 10 feet away. The precise color of the Blue MC13 is what some might describe as a Royal Blue... just a bit shy of hinting at violet. At a distance of 100 feet, the beam is blinding. I found the heat dissipation structure on the Heat Sink generated quite a bit of heat when running in Turbo mode for about 5 minutes. Manker says it can be run for 50 minutes in Turbo, and the Toughened Glass TIR lens with anti reflection coating handles the heat. The MC13 can also be set down in a tail-stand position. The Manker MC13 uses a TIR lens - this is an optical lens that uses total internal reflection (TIR) to focus light into a concentrated beam. This technology is also being used on NASA spacecraft to make their camera lenses smaller and lighter. I suspect folks might imagine that the Blue version (which has the lowest Lumen output) might sound too dim when compared to the other colored models, yet it projects a modest-sounding 115 lumens output with a somewhat astonishing 640meters beam distance (for the Blue model alone). It's one of those things that needs to be seen in order to be experienced. The hue of this blue also reacts with different camera sensors in different ways. Most smartphones can handle the unique blue hue, though some will be overwhelmed with the tone, producing unusual photographic effects. The same with some APS-C and Full Frame camera sensors. You can certainly produce some interesting light-splash effects when directing the colored beam into a room or a structure. A quick double-press of the tail-button immediately sends the beam to Full Power and the MC13 can even run for 82 hours in Moonlight mode at 0.5 lumens. Peak beam intensity is 102,400 cd (on the Blue model). With a healthy battery, it's rated to run for 50 minutes in "Turbo" mode and there's a Strobe setting built-in as well. It's incredibly lightweight at just 136 grams (with the battery) and it fits in most pockets - or you can use the built-in stainless steel pocket clip. At barely 3.5 inches long, it's a tiny little powerhouse. Supplied with a Manker high drain 18350 battery (which has a Type-C USB charging port and charge light built into the battery), there's also a groove cut into the stainless steel tail-cap button for fitting a 1.5 x 6mm Tritium tube - should you wish to add one. And Manker have added a Lanyard Hole as well. This is a fun light to play with and it's certainly much safer to mess about with than UV flashlights. It's well built, has a drop rating of 1M and an IPX-8 rated sealing for water immersion - plus Anti-reverse battery protection & overdischarge protection.