Machined with certified USA 7075 T6 billet aluminum and held to an extremely tight tolerance of .0005 inches using a precision Computer Numeric Controlled (CNC) mill. These Vortex rings are then serialized, vibratory tumbled, bead blasted and finished with a Type III hard coat anodize. Rugged, lightweight, anti-snag design Robust, Grade 8 fasteners 100% made in USA guaranteed for life Available Precision Matched 34mm Rings MPN Height Optical Centerline PMR-34-92 Low .92" PMR-34-100 Medium 1" PMR-34-1.1 Medium Plus 1.10" PMR-34-126 High 1.26" PMR-34-145 High Plus 1.45" Learn More About Vortex Precision Matched Rings Vortex Precison Matched Rings (Set of 2) for 34 mm (1.45 Inch / 36.8 mm) PMR-34-145