*Featuring simple installation and disassembly, it is more convenient to use.The function of this pedal assist sensor is to help extend cycling mileage with good accuracy. *Extend battery life and improve vehicle cruising range. Avoid damage to the battery due to high current discharge *This product is perfectly suitable for bike, electric bicycle, etc. According to the speed of the turn of the foot to identify the power, pedal up in the process of riding is more lightweight and electricity saving. Size:Diameter of outer ring 6.5cm, diameter of inner ring 1.5cm Magnet Quantity: 5/8/12 pcs Wire length: ca. 100cm Wire color: red- positive poles yellow-negative poles blue- signal line Package Include:1Pc * E-bike Assist Sensor - The pedal assist sensor has compact size, is light weight, long durability, anti-shock, anti-corrosion and dustproof, good for assisting electric bicycles. - This speed sensor is a high-tech component designed for electric bicycle with ergonomics. - The 1:1 assist sensor works well for pedal-assist electric bicycles drive system, save your labor while pedaling. - Suitable for almost all electric bicycles available in the market. - Easy to install and use, a good helper for your electric bicycles.