The 3 Port Muzzle Brake features Rugged Suppressors' Dual Taper Locking System, compatible with all of the Rugged Suppressor rifle and multi-caliber suppressors. This muzzle device is designed for reducing recoil when shooting unsuppressed. The 3 Port Brake has a .30 cal aperture, but the 1/2×28 variation can be permanently attached to 5.56 14.5? barrels in order to meet 16? requirements. Available Thread Pitch Options:1/2x285/8x24 Rugged Suppressors 5/8x24 3-Port Brake MB001