Available for standard 7.62x51mm and 5.56A-45 threaded barrels, the Keymount Muzzle Brake is your gateway to silence. When you’re ready for peace and quiet use the Keymount brake to quickly attach your Sandman-L or Sandman-S to your rifle. If you’re not quite ready to turn up the silence, you can still employ the finest brake on the market and experience a flatter shooting rifle with minimal concussion compared to traditional muzzle brakes. Mfg: Dead Air Armament