DEAD AIR 5.56 MUZZLE BRAKE KEYMOThe Dead Air 5. 56 KeyMo Muzzle Brake is a high performance muzzle device designed for 5. 56mm rifles. It serves as both an effective muzzle brake and a quick attach mount for Dead Air Sandman series suppressors. The sealed taper design prevents carbon lock on, ensuring easy suppressor removal. When used without a suppressor, it provides excellent recoil reduction with minimal side concussion. Features Specs: Caliber: 5. 56mm (. 223) Thread pattern: 1