USAGE For rear fork end alignment; USP 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; Tool box 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;