SCTM-37 (Medium) | SCTM-56 (High) Ring Length: 16mm (0.63 inch) Ring Dia.:25.4mm 1" Height (from base to ring center): medium 25.4mm 1.0" | high 29mm 1.4" Weight: medium 114g (4.0oz) | high 125g (4.4oz) Material: 6061-T6 aluminum alloy Finish: Black matte Easy and quick installation Fit on 21mm Picatinny and weaver rail Designed for real firearms With 1 pc torx wrench