Here’s a unique product–a flashlight that doesn’t require batteries, has a “bulb” that doesn’t wear out, and is “almost” indestructible. It is powered by shaking it and can operate underwater.

The NightStar is powered by moving a powerful magnet through a coil and storing the charge in a capacitor. Of course, all of this is built into the more-or-less normal looking flashlight.
More About Nightstar Here