A must have for tritium illuminated red dots - Meprolight M21 Polarizer Kit

functions exactly as intended, providing higher contrast for a dimly illuminated reticle with a bright background. when "off"/rotated for full light passage the polarizer does not cause significant dimming of the target image, so no need to take on and off. I am not running the kill flash as it and the generally blue hue of the host m21 dot does drive for a darker image and thankfully i'm not in a position where reflection off the front glass is a safety issue.