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 1/2-28. Mfg: Knights Armament SPECS: Fits - 1/2-28 muzzle threads. Material - steel. Finish - Matte black. Includes 7-piece shim kit and Rocksett adhesive. 5.56 - Length - 2.20". Weight - 2.7oz. Threads - 1/2-28.