Forward Controls Design Dead Air Keymo Muzzle Brake .223 Remington 1/2x28 Nitride Black. Forward Controls Design is an authorized licensee of Dead Air suppressor mounts. Do not use a crush washer if this is going to be a suppressor host. Specifications for Forward Controls Design 1215KM Dead Air Keymo Muzzle Brake: Manufacturer: Forward Controls Design Color: Black Projectile Caliber: .223 Caliber Caliber: .223 Remington Finish: Nitride Fabric/Material: 4140 Steel Threads per Inch: 1/2x28 Length: 2.402 in Weight: 3.81 oz Package Contents: Forward Controls Design 1215KM Dead Air Keymo Muzzle Brake Single use packet of Rocksett Forward Controls Design 1215KM: 1215KM Dead Air Keymo Muzzle Brake .223 Remington 1/2x28 Nitride Black