WEAVER No base is required for mounting this rings since the bases are molded as one entire piece. Specifications and Features: Weaver Steel Lock Direct Receiver Mount 49814 1" Tube Diameter Scope Pro-View design Direct Receiver Mount Steel/Aluminum Construction Matte Black Fits: Remington Model 4/6/7400/7600 Rifles DOES NOT FIT REMINGTON 750 Please call us with any questions. We will be glad to help. Centark Truck and Equipment Parts 8-5 CST Mon-Fri