The Ruff's Precision Manufacturing Co-Linear Scope Rings have a built in level that is visible from the shooting position with the shooters'non-dominant eye for quick reference prior to the shot.The level also significantly aids in accurate scope mounting by giving reference to the cant of the rifle during the scope mounting process while eliminating the need for multiple small levels and balancing acts! Features6061-T6 aluminum ring body and cap303 stainless steel cross bolt & nut (1/2")Alignment lug to ensure cap/base alignment during cap screw installationLow (.885"), Medium (1.00"), High (1.25") from barrel to center of ring Recommended Torque SpecsCap Screws: 18 in/lbsCross Bolt: 45 in/lbs