Material: Steel Magnets: 12 Disk Diameter: Approx. 65mm Steel Ring Diameter: Approx. 35mm Cable Length: Approx. 90cm 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. Packing List: 1 Pc*Electric Bicycle Assistant Sensor