Eton BoostTurbine is a power source for electronics such as smartphones. For everyday or emergency use, this is a backup battery pack with hand turbine power generator. It features a rechargeable 2,000 mAh lithium battery for power when needed most. Eton BoostTurbine features a Micro-USB DC input to use with most smartphone chargers and a standard USB port for charging mobile devices. When Eton BoostTurbine is charged up, you have enough power to fully charge most smartphones. Crank for one minute to produce power for a 30-second call or a few text messages, then fold the crank neatly into the unit. Press the button and the LED shows the remaining battery charge.