The EOTech EXPS3-4 Sight offers pinpoint precision in close quarter situations. As seen in use by elite military and law enforcement units it's renowned for its ability to function in extreme conditions with holographic image sighting technology to give you true "2 eyes open" sighting with its heads-up display and wide, unlimited field of view. These EOTechA(R) Sights are small, fast and lightweight... without sacrificing an ounce of functionality. Improved battery life over previous models means they won't power down before you do, either. Don't go with anything less on your next mission! Waterproof and fogproof Front windows are solid glass, rear is shatter-resistant laminate Scroll through 30 brightness settings for visibility in any environment Nitrogen-purged optical cavity Fits to standard 1" WeaverA(R) style dovetail or Picatinny rail with tool-less bolt Rugged aluminum hood assembly Non-reflective hardcoat finish