Rugged took their 3 port muzzle brake featuring their dual taper locking system and beefed it up for the.338 and 8.6 rounds.This muzzle device is designed for reducing recoil when shooting unsuppressed.Compatible with rugged's alaskan360 or alaskan360ti.You can also use this brake with your 1.37524 threaded suppressor when you pair it with our r.U.M.(rugged universal mount).*timing shims includedModel: 3 Port BrakeThread Pattern: M18x1 tpi