Specifically engineered for use on our .450 Bushmaster Caliber Rifle and Pistol, this quality steel Nor’Easter Muzzle Brake features three compensating gas ports on top and a closed bottom to help control muzzle rise, and 3 back slanted slots on each side to mitigate recoil and offer a muzzle brake effect. Threading is 11/16″ x 24 T.P.I. (threads per inch). Wrench flats are machined on the threaded end, and the finish is black manganese phosphate. This Compensating Muzzle Brake should be installed with a Crush Washer (Windham Weaponry Part # 12991533-450) for correct port timing on the barrel. Length: 2.1″ x Diameter: 1″, Weight: 3.2 oz. Made in USA.