Features: Electric bicycle speed sensor (known as PAS, wheel mounted sensor). It is a high-tech component designed for electric bicycle with ergonomics. It has superiority to match well with all electric bicycles available in the market. It employs the dual-magnetic loop - Hall elastic angle difference to detect the dynamic torque, which is converted to DC signal and sent to the controller. 1:1 power assist. Make cycling easier and funnier. Spec: Condition: 100% Brand New and High Quality Material: Steel Magnets: 12 Disk Diameter: Approx. 65mm/2.56'' Steel Ring Diameter: Approx. 35mm/1.37'' Cable Length: Approx. 1.1m/43.3'' Weight: Approx. 50g Packing List: 1 x Electric Bicycle Assistant Sensor