Fits Maxima/Weaver Bases and Picatinny Rails CNC machined from sintered steel for superior strength and clamping benefits Square, permanently installed recoil keys for positive engagement of ring to base Rings mount securely around scope using 4 Torx T-15 cap screws, 2 screws for each clamp STANAG 4694 interface allows for better return to zero and rigidity Designed and made in USA