Features: 1. 360 °rotation: can rotate 360 degrees to adjust the position, humanized setting, convenient for all kinds of vehicles. 2. Used to correct rear derailleur lugs have solved many transmission shifting problems, especially positioning rear derailleur systems. 3. Lock and press the sliding bracket to adjust the distance between the measuring rod and the hub, and measure the deviation between the tail hook and the wheel rim. 4. If your rear derailleur is giving you a hard time, not shifting, chattering or jumping a sprocket, then you might have a misaligned derailleur hanger. 5. This tool has enough clearance to help you move around the wheel when you are making the necessary corrections on all your bikes. Notice: xActual color may be slightly different from the image due to different Display and light effect xPlease allow 1-3cm deviation due to manual measurement Description: Size: 395cm Material: aluminium alloy Package List: 1 pcs x Bicycles Derailleur Hanger