What Does UV Filter Do?

While looking at the Fenix T10, I noticed they had a red filter for six bucks. Nice, but I'd like one that would fit the T10. I also noticed that Fenix-store.com had UV filters listed for Microfire. That set me back a bit because in photography books I was given to understand that all glass filters filtered UV. In fact, a car window will filter out UV rays.

Skylight filters filtered out not only UV, but added a touch of warmth to boot. In fact, I preferred the Skylight filters over the UV because they worked much better in shade.

So on flashlights, what do UV filters do?

Thanks!

That's a UV-pass filter, not UV-block filter. It enables you to use a HID lamp as a UV source (AFAIK, HIDs spectrum contains quite a lot of UV - this just filters everything else out).

Ah....that makes sense. Thanks.