Materials:Aluminum alloy。 Motor Voltage:48V .Fit For:Electric Mountain Bike. Product Size:160 x 68 x 80mm. Power:350 W Brushless Motor. Speed:18-30km/h Important:Please see the main picture 2 clearly to confirm that your bicycle can be installed. Package Included: 1 x Booster 1 x Clutch Switch Speed control (handle) 1 x Mounting Baffle 1 x Quick Screw Give away a motor wheel (This product does not have a battery) (This product does not have a battery) (48v lithium and lead-acid batteries are suitable.) Note: - The effect of booster is related to the tread of tire. The surface with shallow tread is better than that with deep tread -4.0 tires, tubeless tires, and solid tires are not supported. --Cannot be installed under general 16 inches. -The effect has a lot to do with tires. The larger the contact surface between bicycle tires and our wheels, the better the effect. Flat tires have a better effect.