Originally developed for the Israeli Defense Force, the Mepro M21 red dot day/night self-illuminated reflex sight represents the best of Meprolight tritium technology and remains in active duty for the IDF, militaries, and law enforcement agencies worldwide. A red dot sight with fiber-optic illumination by day, Meprolight tritium by night, it provides the advantage on any battlefield with no need for batteries, ever. It's rugged, battle-proven construction meets or exceeds rigorous MIL-STD-810 standards to thrive in the harshest conditions. With a large field of view through a 30mm diameter lens, the Mepro M21 sets the standard for the term "Always On, Always Ready". Features: No battery needed No switches, always on, always ready Wide field of view Proven battle sight for militaries and law enforcement agencies worldwide Parallax free 10 year warranty on tritium Specifications: Magnification: 1x Lens Diameter: 30mm Field of View: Unlimited w/ Both Eyes Open Power Source: Fiber Optic and Tritium Aiming Point Diameter: Triangle Dimensions: 4.48"L x 2.16W x 2.75"T Weight: 13.12oz w/ Picatinny Adapter Submersion: Submersion Unlimited Working Temperature: -40AdegF to 140AdegF Mil-Spec: MIL-STD-810