This 3-port muzzle brake is compatible with all SilencerCo ASR Mounts — and with multiple thread and caliber options” you can shoot suppressed for any demand. It offers quick and easy one-hand-on” one-hand-off attachment and detachment. The 3-port design effectively reduces felt recoil and muzzle climb. Each ASR muzzle brake comes with a shim set and rocksett for easy application.