An electric front wheel that instantly converts your bike into an electric bike. 

It has no hub or spokes and instead has a rim and tire that revolve around an empty space in the middle. The empty space is partially occupied by a non-rotating module that contains the 500-watt brushless motor, a removable battery pack and the electronics. Three arms reach out from that module to the inside of the rim, each one equipped with a rubber roller at the end. The bottom roller is powered by the motor, causing the rim to rotate around the module. [Source]