Classic steel, holds scope tightly. Fits Leupold STD, one- and two-piece bases, plus bases from Burris, Millett and Redfield. Mfg: Leupold SPECS: Steel 1'''' (2.5cm), 26mm (1.02'''') or 30mm (1.18'''') I.D. Gloss, polished blue. Matte, matte blue. Silver, satin nickel. Height measurements are from top of base to center of ring: 1'''', 26mm and 30mm: Super Low, .550'''' (13.9mm). Low, .650'''' (16.5mm). Medium, .770'''' (19.55mm). High, .900'''' (22.