Drill and tap mount attaches the scope to your Ruger’s® top strap. Fits Ruger® Redhawk®, Blackhawk® and Super Blackhawk®, and Ruger® GP100®. Accepts Weaver-style rings.
Big Book Catalog, Issue:68, Page:263
SPECS: Extruded aluminum, silver or black, anodized, matte finish. 4½" (11cm) long, 7⁄8" (22mm) wide, 1.3 oz. (38 g) wt. Includes mounting screws. Requires drilling and tapping.