Vortex Optics Precision Matched Rings These Vortex Precision Matched Rings position thecenterof the riflescope tube at a height of 0.92 inches (23.4 mm) from the base. Will only work with Picatinny spec mountswill not work with Weaver mounts. Our Precision Matched Rings are kept in pairs throughout the manufacturing process  ensuring perfection from one set to another. We start with certified USA 7075 T6 billet aluminum and hold it to an extremely tight tolerance of .0005 using our precision Computer Numeric Controlled (CNC) mill. These Vortex rings are serialized, vibratory tumbled, hand-bead blasted and finished off with a Type III hard coat anodize. Sold two rings per package. Hex wrench included. Made in the USA. <span class="a-text-bold">Optical Quality:</span>Vortex uses dense optical glass painstakingly designed, shaped, and polished to eliminate flaws. Sophisticated optical designs and glass result in a brighter, sharper, more colorful image. <span class="a-text-bold">Superior Construction:</span>You may pay a bit more for optics using quality materials, sophisticated designs, and strict tolerances, but the result is greater reliability in the field. <span class="a-text-bold">Attention to Detail:</span>Our standards are exacting. Vortex engineers spend thousands of hours designing every part, testing every component, and scrutinizing every detail. If we dont absolutely love it, we know you wont either. Weight (Per Ring): 65 Grams - 2.3 oz Rugged, lightweight, anti-snag design Robust, Grade 8 fasteners 100% made in USA