Heavy-duty rings and bases are built to withstand extreme service without movement or loss of zero. Larger contact area between the scope/rings and base/receiver for less chance of movement. Large hex nuts on rings allow fast torquing of cross bolts for easy adjustment. Non reflective, matte finish. Mounting screws and Torx head wrench included. Steel Rings - CNC machined from solid 11L17 cold-rolled bar stock, then blued. Aluminum Rings X"X CNC machined from 7075 T651 aluminum alloy and hardcoat anodized for maximum strength and wear resistance. Mfg: Leupold SPECS: Steel or aluminum, matte black finish Rings - 1" (2.5cm) or 30mm (1.18in) inside diameter. Height from top of base to center of ring for both 1" and 30mm: Med. - .84" (2.1cm); High - 1.06" (2.7cm); Super High - 1.4" (3.5cm).