Each Weaver base is machined to the tightest tolerances for a custom fit. They are designed to fight the effects of recoil with a square-cut notch that precisely mates to the sturdy cross bolt in every Weaver detachable ring. Specifications: - Base Type: 1 Piece - Material: Aluminum - Style: Weaver - Finish: Silver Fits: - Smith & Wesson Models 29, 629, 625, 686 & L, K & N Frame Revolvers (Factory Drilled) - Taurus L, K & N Frame Revolvers (Like S&W, Factory Drilled) Note: Mounting Hardware Included.