Product attributes:
The Hanger Genie is a foldable precision tool for resetting rear derailleur hangers and maintaining precise gear shifting. It's compatible with all wheel sizes from 20˝ to 29˝+, and the screws fit directly into the rear derailleur hanger threads. The precision gauge locks in place, so you won't lose your reading when you press it against the wheel in different positions. The tool's rotating base allows you to easily clean the frame while working.