Dead Air Armament Keymo Muzzle Brake M18x1 Thread .338 caliber. When you're ready for peace and quiet use the KeyMo brake to quickly attach your Sandman Series or KeyMo equipped suppressor 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. When it comes to removal the suppressor can be easily removed without carbon-locking onto the mount. 1/2-28 5/8-24 3/4-24 M18-1 & M18-1.5 do not come with timing shims Specifications for Dead Air Armament Keymo Muzzle Brake: Manufacturer: Dead Air Silencers Color: Black Condition: New Package Contents: Dead Air Armament Keymo Muzzle Brake Dead Air Armament Keymo Muzzle Brake - DA104