Burris 25mm Signature Rifle Scope Rings Universal Dovetail are for the shooter who demands the best performance imagefrom his equipment and is a practical thinker. The benefits of this revolutionary design are many. Consistent accuracy. Tremendous gripping power. Scratch-free and stress-free mounting. Scope value preservation. By putting a synthetic pivoting insert within a Burris steel outer ring, your scope-to-ring surface area contact becomes virtually 100%. Burris 30mm Signature Universal Dovetail Ring Pair is shipped with Burris concentric and +/-.010" inserts.