Superior Material: Aluminum alloy are used to effectively improve the edge of the wheel hub, which is light and high end, comfortable and has strong bearing capacity. Low Noise Operation: Electric bicycle rear wheel hub motor is designed for less than 55dB noise, realize noiseless operation, let you fully enjoy the riding pleasure. Waterproof Performance: Strong and durable, fine workmanship, good toughness and good waterproof performance, provide better protection for the internal circuit, making it more durable. Wonderful Riding Experience: Electric bike rear wheel conversion motor is easy to maintain, high efficiency, greatly improve riding fun, suitable for riders who like a challenge. Wide Range of Uses: Rear wheel electric bicycle hub motor is widely suitable for electric bicycles, DIY electric bicycles, electric scooters, folding bicycles, etc. M Efficiency:? 80% Colour: Black Noise. We will reply your message within 48 hours. If you do not receive our reply within 48 hours, pls. Post a message again because sometimes our message system may block some emails. If you are satisfied with our service, pls. Our aim is to provide Level Customer Service, your recognition will encourage us greatly and serve you better. We strive to keep all our customers satisfy. We will do our up most to exceed your expectations in customer service, communication and dispatching of your orders.