Leupold STD 1 inch Extension Rings, Matte Finish Versatile, and available for many different rifles The forward part of the base accepts a dovetail ring, locking it solidly into position; The rear ring is secured by windage adjustment screws 2-Piece bases offer maximum accessibility to the breech area of your rifle Long Range STD mounts provide a 15-MOA slope of built-in elevation compensating for bullet drop at extreme ranges 2-Piece bases fit right and left-hand actions, and reversible bases are available for many actions