A hot water bottle re-breather? For $100?

Hmmm. This guy is definately been diving too much lol. But he does get the thumbs up on being creative with his materials.

Check out the details on his web-page: www.atlimp.com/pend2.htm

BTW - DON'T TRY THIS AT HOME! (You may now continue to the page to figure out how you are going to make your own - crazy)