Battle Arms Development Enhanced Magazine Release, Anodized Finish, Olive Drab Green, Fits AR-15, Aluminum Construction BAD-EMR-OD Precision CNC Machined for billet 7075-T6 Aluminum (not 6061) in an anodized finish" the BAD-EMR features a unique" fully solid V shaped button face with horizontal serrations (no through hole). The concave V-Groove button face offers an excellent ergonomic feel and self-centers the index finger as pressure is applied. The horizontal" parallel serrations help slippage in the vertical orientation while minimizing drag in the horizontal direction for finger retraction. The BAD-EMR also features a lightweight skeletonized back to offset the weight gained from the fully solid button face and slightly increased height to equal the weight of the standard mil-spec magazine release (approximately 0.002 lbs). The BAD-EMR is compatible with all lower receivers that accept mil-spec magazine release buttons.