This Genuine Ruger Factory Accessory is compatible with Ruger-57 Pistol. The factory- manufactured threaded stainless steel barrel accepts any 1/2''-28 (Class 2A) muzzle device. This kit contains a factory-manufactured stainless steel barrel for optimal fit and function. Installing the threaded barrel is quick and easy with no gunsmithing required. Thread protector adapter and wrench included. Made in the USA.