PedalCell consists of two pieces. The Generator attaches to your bike's frame, on the front or back, and touches the rim. When your wheel spins, the side of the rim spins the Generator to create electricity. This electricity is sent up a cable to the second part of the device: the Smart Power Hub with two USB-C charging ports. PedalCell does not use batteries. Our product does safely stabilize power for your devices and can output charge for up to 30 seconds while stopped.