The Ruger SR22 threaded barrel kit contains a factory-manufactured stainless steel barrel for optimal fit and function. It accepts any 1/2"-28 (Class 2A) muzzle device and includes a barrel cap, adapter and wrench. This Genuine Ruger Factory Accessory is compatible with Ruger SR22 pistols bearing serial numbers 361-7XXXX and higher. Does not fit the 4.5" length barrel model. Made in the USA.