Leupold STD Browning X-Bolt 2 Piece Base - Matte Black The Leupold steel standard bases and rings are the most versatile of any mounting system they offer. The rear ring is secured by windage adjustment screws, allowing the scope's internal adjustments to be reserved for precise sight-in. Additionally, shims can be used for gross elevation adjustment, reserving the scope's elevation adjustment for bullet drop compensation dial applications. Features: Forged and Machined steel construction Versatile, and available for many different rifles Windage Adjustable (STD Mounts) - The forward part of the base accepts a dovetail ring, locking it solidly into position. The rear ring is secured by windage adjustment screws Long Range STD (STD Mounts) - Long Range STD mounts provide a 15-MOA slope of built-in elevation compensating for bullet drop at extreme ranges 2-Piece bases offer maximum accessibility to the breech area of your rifle 2-Piece bases fit right and left-hand actions, and reversible bases are available for many actions STD rings are engineered to match up with STD 1-Piece and STD 2-Piece bases. Five different ring heights are available for STD bases