Each Weaver base is machined to tight tolerances for a custom fit. These aluminum bases offer maximum strength for rings to hold tight. This base offers the rock solid Weaver cross-lock design to fit a variety of rings. Misc N/A Type 1-Piece Base Model Top Mount Base Style Weaver Finish Black Matte Pieces 1 Series 40A Gun Type Rifle Material Aluminum Mount Type To Receiver Rings Included No