This 30 Degree MOA scope base is designed for long-distance shooting with the Ruger Precision Rimfire. The rail is specifically engineered to fit the factory scope mount holes on the gun’s receiver. MIL-STD Picatinny slot-and-rail spacing accommodates Picatinny or Weaver scope rings. The one-piece design is precisely machined from billet aluminum. The base measures 5.25 inches long, has a hardcoat anodized finish, and includes four TORX mounting screws and a T-10 wrench. Made in the USA. Genuine Ruger Factory Accessory.