Engine cut sensor on derailleur.
This sensor, which connects directly to the yellow output of the motor, allows you to automatically switch off the motor when you change gear and thus avoid banging your chain on the chainrings!
This addition to our kits is the ideal solution if you want to preserve your derailleur, when you change gear a motor cut is done!
If your derailleur cable is frayed, you should get the version with derailleur cable, because the cable goes through the sensor and frayed cable will make it impossible to pass the cable through!