Heights: Low and Medium for scopes w/objective diameters to approximately 1.75"(44.45mm). High for objectives above 1.75". Extra High for scopes with objectives up to 60mm. Mfg: Weaver SPECS: Aluminum lower; steel cap, screws, crossbolt and nut. Satin Blue, Matte Blue or brushed Stainless finish. Height (above base): 1" diameter – Low, .090" (2.28mm); Med., .164" (4.16mm); High, .332" (8.43mm); X-High, .560" (14.2mm). 30mm diameter – Low, .290" (7.3mm); High, .485" (12mm