. Shimano TL-RD11 Derailleur Hanger Alignment Tool . For rear fork end alignment . Universal size to fit most wheel sizes (20-29 inch) . Precise numerical measurement with scale . Rotatable scale enables easy operation without interference by chain and seat stays . Index system makes it possible for the scale to go back to the measurement position after rotation . Narrow alignment boss to fit a wide variety of bikes . Toolbox friendly telescopic handle . Ergonomic handle . Threading a bolt to the M4 female thread at the end of the spindle stabilizes and reduces the load on the fork end thread during the alignment operation . Chrome plated carbon steel for durability and rigidity