Here’s a great piece for all you road warriors out there–the travel alarm clock is a great invention, especially when you don’t trust that cheap clock radio the hotel leaves by your bedside any farther than you can throw it.

But chances are you’ve run out of batteries for your travel alarm clock before.  And what do you do about that?  Hope you can find a store before you go to bed?  Try and recharge those batteries via any of a hundred methods?

How about just using a travel alarm clock that runs on water, like this one?  That’s right–water.  You fill up the reservoir with water, and an electrode inside converts the water into power for the alarm clock.  Best part?  This nearly completely self-powered clock runs a meager thirty dollars, if you’re interested in getting one.