UTG MNT-757: Every weapon with an optical sight should have an auxiliary sighting system. If your optic depends on batteries, backup sights are an absolute necessity. Designed for M4/M16/AR-15 rifles, and other weapons with same-plane mounting locations and similar sight height, this folding rear back-up sight has a low-profile, lightweight design. * Precision Machined from Aircraft Aluminum with a Matte Black Finish * Spring-loaded Posi-lock Push Button Activation Automatically Deploys Sight Tower and Prevents Sight Tower from Collapsing when Deployed * Uses Standard A2 Front Sight Post, Interchangeable with Other Aftermarket Posts with Equivalent Dimensions * Utilizes a Single locking Torx Screw with Low Profile Mounting Base and Square-shaped Integral Recoil Stops for a Secure Zero Hold and Return to Zero on MIL-STD-1913 Picatinny Rails * Designed to Match MNT-957, UTG ACCU-SYNC(R) Spring-loaded AR15 Flip-up Rear Sight