Precisely align and center your 30mm maintube riflescope with this set of Burris Optics high XTR Signature Scope Rings. The rings position the center of the scope 1.5" above the top of the base, and come with multiple proprietary Pos-Align inserts which allow you to virtually align your scope without touching the internal adjustments - giving you more adjustment range than your scope has internally, and leaving the reticle closer to the center. Using the inserts singly or in combination can add 0, 5, 10, 15, 20, 25, 30, or 40 MOA of cant on the scope mount, leaving the internal adjustments unchanged. This adjusted scope positioning is ideal for medium- and long-range shooting, when shooting under extreme conditions, or for scopes with a limited internal adjustment range. The rings also correct misalignment caused by off-center receiver holes or bases. These aluminum alloy scope rings have a matte-black anodized finish, and are equipped with self-centering steel clamps to provide a solid connection to any Picatinny/Weaver rail.