The Leupold steel standard bases and rings are the most versatile of any mounting system we offer. The rear ring is secured by windage adjustment screws, allowing the scope's internal adjustments to be reserved for precise sight-in.Features: Bases are available for many popular rifle modelsForged and machined steel constructionVersatile and available for many different riflesThe forward part of the base accepts a dovetail ring, locking it solidly into position, the rear ring is secured by windage adjustment screwsLong Range STD mounts provide a 15-MOA slope of built-in elevation compensating for bullet drop at extreme ranges2-piece bases offer maximum accessibility to the breech area of your rifleSTD rings are engineered to match up with STD 1-piece and STD 2-piece bases, five different ring heights are available for STD bases