Signature rings are available for all types of optics and bases. Pos-Align inserts offer tremendous gripping power and durability and will not damage the scope finish. The benefits of this revolutionary design include consistent accuracy, tremendous gripping power and scratch free and stress free mounting. By putting a synthetic pivoting insert within a steel outer ring, your scope-to-ring surface area contact becomes virtually 100%. *Come with a spare set of clamps designed to fit 11mm dovetails.