For rodent urine, 390 nm, despite many places that sell lights for this using that, is not that great, as in, it sucks.
365 nm is a LOT better.
The power ratings vary tremendously, think of it as the "throw" number....but make a tremendous difference in that application.
The beam angle is the other issue.
For example, a guy checking a $20 is right on top of it...inches away. Its hard to miss a bill in your hand, and, you know where to look, etc.
A guy looking around a warehouse or basement, etc, for urine tracks, doesn't know if they are there or not, and, is NOT inches away typically. IE: You would rather be standing, and shine the light around like a flashlight, and see what fluoresces, than have to be on your knees looking at every square inch manually, etc.
You would RATHER the UV beam be wide enough to give context/where the trail came from/is going, that its not an efflorescence deposit, and so forth....than be a teeny glowing point that you have to mentally stitch together with the other wee points to make a picture, etc.
That all takes a lot of power. (Just like lumens vs lux, etc) - The tighter the beam pattern, the smaller the dot of light, but the more watts per square inch you get to make micky's wee glow. Spread the same watts out, and its less per square inch....etc.
Something like a (Nichia) NVSU333A U365 LED puts out ~ 3,640 mW at 365 nm for example. With the right optics, its a very good option for that application.
And so forth.
Forget the "dual purpose" versions...the beam compromises are not worth it...and just get a dedicated UV light....for your application, its a better solution.
The flashlight can be a better flashlight, and the UV light can be a better UV light...as with two LED, which of them is optimally located in the lens, etc, to focus best?
Answer = NONE.
