The Sinewave Cycles Revolution is a bicycle dynamo powered USB charger. It converts electricity generated by hub and bottle dynamos to USB output. The revolution allows users to charge USB-powered devices while riding. A built in overload protection circuit prevents the unit from drawing too much power and over heating. The electronics are encapsulated in epoxy so they cannot be damaged by dirt, water or vibration. Use it to charge a cache battery such as the Solio Bolt or to charge a device directly while riding. If using a Shimano or Sanyo dynamo hub no connectors are required. If using a Schmidt hub use the piggyback connectors (2 included) to wire in parallel with the light or use the straight connectors (2 included) when using the Revolution alone. The Sinewave Cycles website has a helpful FAQ page.