From PSWPower

Metal gear Shift Sensor for Bafang BBS01B BBS02B BBSHD Mid Drive Motor Gear Sensor Electric Bicycle Conversion Three Core Waterproof Connector

The popular Gearsensor (for derailleurs)used with the Bafang mid drives BBS01B/02B and BBSHD to cut motor power while shifting.  Connects into one of the brake connectors or, on some of the newer Bafang mid drives, an extra 4th cable from the controller. Stops heavy torque “slamming” of the chain.

Don't include electrical lever brake

Compatible with all Bafang MID Drives motor 36v 250w, 350w, 500w; 48v 350w, 500w, 750w,1000W cable

Y-SPLITTER 1T2 cable can be used on bafang BBS01 /BBS02 /BBSHD mid drive motor,there are another cable can connect gear sensor.

Package include:
1PCS Metal shift sensor or Plastic shift sensor or Y-SPLITTER 1T2 cable