Vortex begins with certified USA 7075 T6 billet aluminum and uses only an extremely tight tolerance when manufacturing the Vortex Precision Matched 1 Inch Rings. These one inch rings are kept in pairs throughout the manufacturing process — ensuring complete accuracy when making each set of rings. They are then serialized, vibratory tumbled, hand-bead blasted and finished off with a Type III hard coat anodize. They will work with both Picatinny and Weaver Style mounts. They are sold in pairs of two rings per package. A hex wrench is included in each package. These Vortex Precision Matched Rings position the center of the riflescope tube at the height provided above. It is measured from the base of the mount to the center of the riflescope. The Vortex Precision Matched 1-inch rings are 100% made in the USA and guaranteed for life.