Stern Defense SD RBC45 Muzzle Device Black 003-SD RBC45-D1-M. Which is especially helpful on short barreled rifles and pistols. Machined from 6061 aircraft grade aluminum billet and hardcoat anodized. 3.25 inches long and 1.2 inches in diameter. Specifications for Stern Defense SD RBC45 Muzzle Device: Manufacturer: Stern Defense Additional Features: Threaded .578-28 Condition: New Color: Black Fabric/Material: Hard-coat Anodized Features of Stern Defense SD RBC45 Muzzle Device 6061 aircraft grade aluminum. Hard-coat anodized. Sturdy construction. Light weight construction. .45 CAL Threaded .578-28 Notes: All S.D. .40S&W barrels are threaded with .45 CAL threads (.578-28) to accept .45 CAL muzzle devices. Comes with crush washer. Package Contents: Stern Defense SD RBC45 Muzzle Device Stern Defense 003-SD RBC45-D1-M: SD RBC45 Muzzle Device Black 003-SD RBC45-D1-M Black