Just crank the handle and it's a self powered flashlight while also generating common DC power.
Ideal as a battery replacement for a wide variety of basic electricity experiments, the Hand Generator is a low voltage power source that lets you create electrical current by simply turning a crank.
Made from a sturdy, see-through plastic with nylon-plastic gears and handle, the Hand Generator is designed for student use and abuse. It produces up to 7 volts of DC current. You can reverse polarity by simply cranking the handle in the opposite direction. And, when powered by another Hand Generator, it acts as a motor. Includes a spare light bulb.