These Sensors can attach to your existing brakes, turning them into 'e-brakes' that will automatically cut your motor power when the brake lever is depressed. The sensor body has double sided mounting tape to fix to your brake housing, and there is a magnet that you can zip tie or glue to your brake lever (as seen in photo). As long as the Sensor and the Magnet are close, the motor will run, but when you pull the brake lever, the magnet moves away from the sensor, instantly cutting power from your motor. This provides additional safety - ensuring you do not accidentally still power on when attempting to brake. Efficiency is also increased, as these ensure that you will not ever brake against your motor power, which also causes strain on both components.