Guntec USA has been manufacturing AR-15, AR-308 and AR 9mm accessories since 1989. The goal is to distribute excellent quality, at an economical value. Specifications for Guntec USA AR 9mm Mini Slip Over Barrel Shroud w/Multi Port Muzzle Brake: Manufacturer: Guntec USA Caliber: 9mm Luger Finish: Anodized Fabric/Material: T6 Aluminum Threads per Inch: 1/2x36 Outer Diameter: 1.1875 in Weight: 3.3 oz Condition: New Features of Guntec USA AR 9mm Mini Slip Over Barrel Shroud w/Multi Port Muzzle Brake New micro design. Covers 1 3/8in of the barrel. Threads begin approx 1.25in down the shroud. Dual purpose unit, functions as a Barrel shroud and a muzzle compensator. Slips over barrel and threads down from the inside. Multi porting Gatling Gun style muzzle comp reduces felt recoil up to 70 percent. Designed for use on AR pistols. Package Contents: Guntec USA AR 9mm Mini Slip Over Barrel Shroud w/Multi Port Muzzle Brake