Rock River Arms 9mm Operator Muzzle Brake Black. . Established working with some of the most heavy duty and long lasting components available these Muzzle Brakes & Compensators through Rock River Arms will provide you with something that will give years of stability. Rock River Arms has been making top quality products for a number of years and the Rock River Arms 9mm Operator Muzzle Brake is their very own approach to showing you how much they are concerned. At OpticsPlanet we ensure that it is our responsibility to purchase the most suitable product for all your specifications and featuring the Rock River Arms 9mm Operator Muzzle Brake is one thing that we're delighted to offer. Specifications for Rock River Arms 9mm Operator Muzzle Brake: Manufacturer: Rock River Arms Color: Black Projectile Caliber: .355 Caliber Threads per Inch: 1/2x36 Length: 2.25 in Weight: 3 oz Package Contents: Rock River Arms 9mm Operator Muzzle Brake Rock River Arms 9MM0117OP: 9mm Operator Muzzle Brake Black