The #19(TM)LD ACOG(R) MK-II Dual Lever Mount raises the ACOG(R) by only 3/16"" off the top of your rail. The mount is approx. 3 3/4"" long to use up as little rail space as possible. The new MK-II Lever(R) features a built-in precision adjustment wheel allowing fingertip (no tool) selection to desired tension to fit variations in 1913 Mil-Std dimensions. The mounts adjustment wheel comes pre-gauged and locked to the center of the Mil-Std Dovetail specs.