The Ruger RXM Threaded Barrel with Recoil Spring is a genuine Ruger factory accessory is compatible with Ruger RXM pistols originally equipped with a 4''non-threaded barrel. The factory-manufactured, threaded alloy steel barrel accepts any 1/2''-28 (Class 2A) muzzle device. This kit contains a factory-manufactured alloy steel barrel with black nitride finish for optimal fit and function. Installing the threaded barrel is quick and easy with no gunsmithing required. Thread protector and threaded barrel guide rod assembly included. Features4.5" Threaded BarrelThread ProtectorGuide Rod Assembly includedEasy to install Note: Pistols with threaded barrels are not available in all states and locales due to laws containing feature-based restrictions. Prior to purchasing, please check your state and local regulations to verify that you may legally possess such firearms.