The Burris Optics 420520 Signature 1" Medium Gloss Black Zee Ring (Pair) is for the shooter who demands the best performance from his equipment and is a practical thinker. The benefits of this revolutionary design include consistent accuracy, tremendous gripping power, scratch-free and stress-free mounting, scope value preservation. By putting a synthetic pivoting insert within a Burris Optics steel outer ring, your scope-to-ring surface area contact becomes virtually 100%. Burris Optics Signature 1" Zee Ring Pairs fit Weaver-style bases. Prevent "Ring Marks" On The Finish Of The Rifle Scope Tube By using precision-made, tight-gripping inserts made of a dimensionally-stable synthetic material, the riflescope is not scratched or crushed which often occurs with conventional rings. With Universal Dovetail Signature Burris Optics 1" Rings, when the scope is mounted in different positions or moved to another firearm. Grip The Scope Better Burris Optics Concentric synthetic inserts Gripping the rifle scope tube are made of a material slightly softer than the hard-coat anodized rifle-scope tube. The Burris Optics inserts are manufactured by a process that nearly eliminates tolerances and produces incredibly consistent parts. The inserts are slightly wider than standard BURRIS steel rings which increases the potential surface area contact by 12%. (Burris Optics standard riflescope rings already provide 10% to 30% more gripping area than many other popular brands.) With the Burris Optics synthetic inserts pivoting on all axis, they grip the entire surface area of the scope tube rather than only a portion of the tube as is the case with unlapped standard steel rings. Permit The Scope To Be Mounted Without Stressing - the self-aligning synthetic inserts The pivot within the ring housings to eliminate any axial misalignment and induced stress on the riflescope. Hunters and competitive shooters alike can experience temperatures from 10 degrees to over 100 degrees and at even greater extremes. As an aluminum rifle scope and steel firearm expand and contract with temperature changes, the rifle-scope will maintain point-of-impact integrity much better if it is mounted stress-free.