The Vortex Precision Matched Rings (Set of 2) 1-Inch (.76 Inch / 19.3 mm) Rings are made out of durable 7075 T6 aluminum and are milled with a precision Computer Numeric Controlled mill giving them a tight tolerance of .0005 inches. After being serialized and vibratory tumbled, the parts receive a bead blasting and are given an anodized, hard coat, Type III finish. These rings feature a durable anti-snag design and are so light they will hardly add any weight to your rifle build. And as always, Vortex offers a 100% Lifetime guarantee. For safe and accurate installation, torque the base clamp screws to 45–50 in-lbs and the ring screws to 15-18 in-lbs. Box Includes: Torx wrench 2 Precision Matched Rings with grade 8 fasteners. Certified USA 7075 T6 Billet AluminumPicatinny & Weaver rail compatible Vortex Optics Vortex Precision Matched Rings (Set of 2) 1-Inch (.76 Inch / 19.3 mm) Weaver PMR-01-76-W