Designed according to the size of the inner eight-speed hub. The outer diameter of the main body is only 80mm; the rated parameter is 36V / 220~250W; it can be adapted to disc brakes or V brakes. The product weighs 1.7kg and can achieve a maximum power of 500W. It has an ultra-wide efficiency platform with a maximum efficiency of up to 80%; its no-load noise is less than 55dB; its protection level reaches IP65; it is an excellent choice for urban and road bikes.