Dead Air Armament Muzzle Brake Mount, 5.56MM, 1/2X28, Fits Sandman DA101 Available for standard 5.56x45 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(TM)" Sandman-S(TM)" Sandman-K(TM) 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.