This 3-port muzzle brake is compatible with all SilencerCo ASR Mounts. 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. Product Specifications Manufacturer : Silencer Co Caliber/Gauge : .46 Caliber Length : 6.5 Model : ASR Package Height : 1.4 Package Width : 4.6 Product Type : Accessory-Silencer Accessories Shipping Weight : 0.25 Thread Pattern : 5/8"-32 tpi