STANDARD DUTY BASE - Nightforce Standard Duty bases are a quality, affordable solution for ensuring that your scope is firmly mounted to your gun ALUMINUM HARD ANODIZED MOUNT - These aluminum bases are machined to Mil. Std. 1913 rail specifications and hard anodized for durability and scratch resistance PICATINNY-STYLE BASE - Picatinny has a slightly wider, and slightly deeper slot; the picatinny rail also has a standardized spacing of the slots, and the slots typically extend down the length of the rail 1- PIECE CONSTRUCTION - Milled from a single piece of lightweight aluminum; precise scope retention; ambidextrous design; available with zero elevation or 20-MOA for long-range shooting MAINTAINING - Clean all mating surfaces thoroughly before mounting; use a torque wrench and do not exceed recommended torque values for base screws: 25 in-lb