Important Note:This Item Is for the Bike That Uses the Hub Diameter less than 36mm.This Item Doesn't Include Battery or Charger.This Is Our Newest Kit for Electric Common Bike, This Kit Mounts the Sprocket on the Wheel Spokes, so It Fits Most of Bicycle Wheel.Motor Use Freewheel so When Wheel Rotating, the Motor Will Not Rotate, Just like a Normal Bike, This Can Reduce Resistance.The Thumb Kit Includes:1. 1x Brush Motor with Freewheel2. 1x Chain3. 1x Customized Sprocket & Components4. 1x Motor Controller5. 1x Mounting Plate + Bolts6. 1x Wuxing Thumb Throttle (with Battery Indicator & Switch Button)