The Midwest Industries QD Optic Mount provides the smoothest functioning QD lever on the market! Superior clamping that will not damage or coin the rail surface Extremely smooth in operation with a multi-facetted adjustment nut to get the exact tension required by the operator Fully adjustable with no tools required, can be adjusted to fit rails not machined to mil-spec tolerances Hole spacing from center to center 1.800 Overall length 2.30" Weighs only 2.0 oz. Precision machined for optimum return to zero performance and reliability Hard coat anodized 6061 aluminum for a lifetime of service Patented QD lever by Elite Defense Mfg: Midwest Industries