Weaver’s precision-built all steel bases are machined to tight tolerances for a custom fit and a square-cut notch mates to the sturdy cross bolt in every Weaver Detachable ring. Custom hardened fastening screws included. Specifications: – Package Includes 1 Base – Material: Steel – Style: Weaver – Finish: Matte Black Fits: – Browning BLR – Colt Coltsman in 223, 243, and 308 cailber (round receiver) – Mossberg Models 810, & RM7 (Rear) – Sauer SHR 970 – Western Field 730 (Rear) – Winchester 52 with the Hole Spacing Different (Rear) Note: Mounting Hardware Included.