The first reflex sight in the world designed for close quarter combat, the Mepro M21 by Meprolight has been combat-proven by one of the most elite fighting forces in the world: The Israeli Defense Forces. The reflex sight has a large display that allows shooters rapid target acquisition with both eyes open. Reticle illumination is achieved by a protected fiber optic light collection system during the day and by a self-powered tritium light source at night. Transition between the two systems is instantaneous and automatic to assure good contrast between the aiming dot and the target area. The M21 is night vision compatible and does not require switches or batteries.