The LensAlign Long Ruler Add-On for LensAlign MkII is an accessory for the LensAlign MkII focus calibration system that allows you to measure camera/lens combinations with Depth of Field values that exceed the capabilities of the standard LensAlign ruler, specifically telephoto lenses at long distances and wide angle lenses. This kit can be fitted to any existing LensAlign MkII system. It includes a large ruler (approximately 2.5 inches wide by 32 inches long) and a large focus target. This add-on requires a LensAlign MkII (not included).