This set of two 34mm Vortex Precison Matched Rings are made of 7075 T6 billet aluminum with a tolerance of .0005, vibratory tumbled, hand-bead blasted, and finished with a Type III hard coat anodize. These Vortex Precision Matched Rings position the center of the riflescope tube at a height of 1.45" from base and only works with picatinny spec mounts.