The Phase 5(TM) OMR (Oversized Magazine Release) is a drop-in two-piece assembly that replaces the Mil-Spec magazine release button. Installation is easy and requires no gunsmithing. Both the OMR button and paddle are machined from 6061-T6 billet aluminum for a lightweight, strong design.Features:- Larger contact surface than a Mil-Spec magazine release button- Ergonomic pocket on surface of paddle for your finger- CNC machined from lightweight 6061-T6 billet aluminum for strength- Compatible with Extended Bolt Releases- Compatible with Anti rotation trigger/hammer pin setsFits AR 5.56/.223 and 7.62/.308 receivers (does not fit AERO M5)Proudly made in the U.S.A., with U.S.A. sourced material.