This is an accessory Green Filter Adapter for the MF Tactical R5-350-1 and R5-350-5 flashlights (NOT compatible with the compact R5-350-1C+ or R5-350-3C+ models). This filter adapter easily replaces the standard clear lens and bezel assembly. Just unscrew standard bezel and screw on the Green Filter Adapter in its place. This lens is made of hardened mineral glass, which is resistant to scratching or breakage. It will also outlive and outperform similar products made of plastic.
A green filter is used when you need more light, but you dont want others seeing you easily. Green light diffuses much more quickly than do other colors, so your beam is not as easy to see from a distance.