Provides Extremely Fast, Heads Up Target Engagement For Close Quarters & Long Range Shooting

Flush-mounted control buttons positioned on the left side of the unit ensure easy, fast access when back-up iron sight or EOTech Magnifier is installed. Integral mount with knurled cross-bolt locks securely MIL-STD 1913 Picatinny and Weaver-style rails; zero is repeatable to 1 MOA after removing and re-mounting. Front one-third of the base underside is elevated .275" (7mm) for clearance over delta ring and standard military-style plastic handguard. Submersible to 33 ft. depth. Models 516 and 556 occupy only 3¼" of rail space, leaving adequate room for a backup iron sight. Both have an easy-to-acquire tactical reticle with a 1 MOA dot inside a 65 MOA ring and provide up to 1,100 hours of continuous operation on two (2) 3 volt CR123A lithium batteries, included. Model 556 is also compatible with Gen I-III+ night vision systems; 1000:1 night vision brightness range with NV switch engaged. Model 557 employs a ballistic matched reticle calibrated for the M4 carbine, with four vertically aligned 1 MOA aiming dots for target distances of 0-300m, 400m, 500m, and 600m. Fully compatible with Gen I-IV night vision systems; night vision brightness range of 1000:1 with NV switch engaged. Powered by two (2) common 1.5 volt AA alkaline (included) or lithium batteries; 1,000 hour continuous battery life with lithium or 600 hours with alkaline. Requires 3¾" of rail space. Model 517 is powered by two common 1.5 volt AA batteries for 600 hours of continous operation with alkaline batteries or 1,000 hours with lithium cells. Reticle is a 65 MOA circle with a 1 MOA center aiming dot. Requires 3¾" of rail space. Buttons positioned on left side of housing for easy access when G23 Magnifier is mounted behind sight.