Knight's Armament QDC (Quick Disconnect Coupler) MAMS (Multi-Axis Muzzle Stability) Muzzle Brakes act as a quick detach mounting platform for a companion KAC QDC sound suppressor. Standing alone, the brake kits make excellent muzzle brakes, reducing felt recoil and diffusing blast. Machined from steel, these muzzle brakes feature a matte black finish. Each muzzle brake kit includes a 7-piece shim kit and Rocksett adhesive for installation. Available in 5/8-24 threads. Mfg: Knights Armament SPECS: Fits - 5/8-24 muzzle threads. Material - steel. Finish - Matte black. Includes 7-piece shim kit and Rocksett adhesive. 7.62 - Length - 2.20". Weight - 2.7oz. Thread - 5/8-24.