PAS for short, magnetic point assist. It belongs to the sensor. In the assist mode, the controller controls the power output of the motor according to the signal feedback of the boost. Using the principle of Hall sensor, when you are riding, the pedal rotates to generate current through the PAS, and then assists the bicycle to move forward. Generally, the more magnetic points, the higher the sensitivity of the sensor. [Material]made of high-quality plastic and metal materials, impact-, and sturdy, can be installed without removing the handle, and quick installation [Applicable voltage]Suitable for most electric bicycles and scooters, suitable for 36V/48V voltage Colour:Black Material:plastic Size:about6.7x7.9cm Package Contents: 1 * Sensor Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.