An all steel yoke tightens on the frame for recoil proof performance. This system, with quick detachable medium rings included, offers versatility for scope changes and makes your pistol a more accurate tool for hunting and shooting. Specifications: - base type: 1 piece base - material: steel and aluminum - style: Weaver - ring diameter: 1" - finish: gloss black fits: - Ruger BLACKHAWK, super BLACKHAWK (except .357 maximum caliber) notes: - comes with two Weaver rings for 1" scopes. Measure .171" from base to scope tube. - attaches to the gun in front of the cylinder. - mounting hardware included.