The compact CELF-HELP Light is powered by simply using the winding handle to recharge the internal power cell. The LED light combinations allow you to switch on two, four, all five, or just the red light for eye-friendly night viewing. It will last up to 30 minutes with just 1 minute of winding time…It also has the added benefit of being able to recharge a dead cell phone battery in emergency situations. It comes with adapters, which can be used to recharge most major brand cell phones.