The Meprolight Day/Night Self-Powered Red Dot Reflex Weapon Sight MEPRO-M21 provides constant, all-light aiming capability, without the need of a battery supply. Reticle illumination on this Reflex Sight by the expert engineers at Mako-Group is achieved by a protected fibre optic light collector system during the day, and by a miniature self-powered tritium light source at night. Night vision compatible, the Meprolight Self Powered Reflex M21 Tactical Sight features a large 30mm diameter lens that provides rapid target acquisition with both eyes open. This MeproLight Red Dot Sight has a quick-release Picatinny mount that perfectly retains zero. Designed through close collaboration with Israeli Special Forces, the Meprolight Self-Powered Red Dot Reflex Weapon Sight is the first reflex sight in the world designed for close quarter combat.