This tool is intended to provide the leverage necessary for straightening damaged derailleur hangers on modern mountain bikes. 10″ long, the 10mm – 1.0 bolt provided allows the tool to be installed in place of the derailleur for minor realingnment of the mount without damaging the threads. If a pry bar or adjustable wrench is used the mount can bend at the hole leaving the threads unusable. Please understand that this tool is not designed or intended as a measuring instrument of any kind. It will be delivered exactly as shown in the pictures, no pointers, gauges or indicators of any kind are included. The length is sufficient to perform the task it is intended for.