One-piece Picatinny scope base is designed for use with Ruger American Rimfire rifles chambered in .22 LR. The rail is engineered specifically to fit the American Rimfire 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.