Variable speed mountain bike dedicated rear drive kit==Item List==1) 36V 250W is suitable for rear drive motor x12) 36V 21Ah triangle battery (including battery and bag) x13) Matching 2A charger x14) Supporting controller x15) Bicycle rotating handle (throttle) x16) Brake handle with power-off function x27) Car light combination (with horn) x18) Booster x19) Waterproof quick disassembly lead x110) Controller box x111) 10m winding tube x112) Motor wire guard & motor fixing bolt==Package parameters==Function: Cruise control mode & three-speed modeMotor type: brushless, toothed, rear-drive spoke type motorMotor shaft length: 208mmMotor weight: 2.7kgBrake type: disc brakeModels used: variable speed cars, mountain bike modificationMotor color: blackMotor voltage: 36VOpening width: 135mmNumber of spokes: 36 holesMaximum operating speed: about 40km/hMotor lead form: waterproof and quick disassembly leadLead length: 900mmFlywheel type: spiral flywheelDisplay: vehicle speed, mileage, power==Battery parameters==Nominal voltage: 36VBattery capacity: 21AhBag size: 230x80x80x180x90x195mmBattery size: 215x70x65x170x80x175mmOutput voltage: 28-42VTotal weight: 3000gSupport motor power: 50W-800WSupport charging current: 0.2-5AOperating mileage: about 30-40KMIf you need a larger capacity battery, please contact us, you can customize the battery according to your requirements. Suitable for DIY electric bicycles, turning your ordinary bicycles into electric bicycles. The brushless hub motor runs quietly, allowing you to fully enjoy the driving pleasure. High strength, high efficiency, greatly improve riding pleasure, suitable for cyclists who like challenges. Simple to use, sturdy and durable, and long service life. Provide a lot of help for long-distance, labor-saving, farther and more beautiful places.