One-piece Picatinny 20 MOA Scope Base is designed for use on short action Ruger American Rifles. The rail is engineered specifically to fit the American Rifle factory scope mount holes on the gun&';s receiver. MIL-STD Picatinny slot-and-rail spacing accepts Picatinny or Weaver scope rings. One-piece design is precision-machined from billet aluminum. Base is 6" long with a hardcoat anodized finish and includes (4) TORX mounting screws and a T-10 wrench. Made in the USA. Genuine Ruger Factory Accessory