These rings are precision machined to true MIL-STD 1913 specs to fit Picatinny-type bases such as Brownells Modular Flattop Riser Mount and Picatinny Scope Bases. No special wrenches needed for installation. Underside of ring is undercut with a rounded radius that offers extra clearance for finger tightening the nut and for final tightening with a standard socket or flat-blade screwdriver. Extra-strong U.S.-size hex nuts have a deep slot that provides maximum engagement of screwdriver blade to help prevent slippage and slot damage-you can even use a U.S. quarter in a pinch. Crossbolt has a square shank that serves as a recoil lug to solidly engage scope base when properly installed Mfg: Brownells SPECS: Rings sold in pairs. Models available to fit 1" and 30mm scope bodies. Steel – 4140 billet steel, black, matte, oxide finish. Aluminum – 6061 T6 aluminum billet, hardcoat anodized black, matte. Heights measured from top of base to center of ring: Low – .825" (2.1cm); Med. – 1&quo
