The NEW Gear sensor (for derailleurs and Internal Hubs) used with the Bafang mid drives BBS01/02 and BBSHD to cut motor power while shifting. Connects into one of the brake connectors. On some of the newer Bafang mid drives, an extra 4th cable from the controller is provided. This helps prevent heavy torque while shifting
See this video for installation tips https://youtu.be/cRo6gbOdh-I
