635 nm Red Laser Dot Aim Laser & Laser Cover 5 Levels of Brightness for red and Green make this scope work effectively under low light condition Waterproof-Shockproof-Fogproof Integral Windage and Elevation Housing w/Dual Sealed O-Ring & One Piece Internal Tube to Guarantee Reliability, Accuracy and Consistency Top quality Emerald Bright Coatings for Optimum Light Transmission Easy to setup, fits any 20mm rail Matte black Finish