Dickie D picked up the "Hydra Light," from "As Seen on TV." Here's a bit of the hype on Amazon: ACTIVATED BY WATER: Hydralight 2 in 1 doesn’t need any electric battery to charge, it runs on water and no specific type of water is required to run hydralight, any kind of water: Regular, Distilled or salt will do the job, 2 IN 1 Design: You don’t have to buy both flashlight and lantern separately. Hydralight becomes flashlight and lantern. Just dip the fuel cell for 10 to 12 sec in water, shake it off, and then we're set to go, with up to 100 continuous hours on a single water dip. And it has a 25-year shelf life.
And now the downside you don't read on the package. OMGchad said he and some of the TWiT gang learned a lot about fuel cells when he worked at the Brickhouse. Once activated, a fuel cell can't be turned off. So whether your flashlight is "on" or "off" the fuel cell is active. So the 100 hours of use means 100 continuous hours! Basically your flashlight works for 4 days plus, then the fuel cell has to be reactivated. Do this 3 times and the fuel cell is used up. A new fuel cell was $13.55 on 8/31/19! Reviews are not great on Amazon, either.
Giz Wiz Video: https://youtu.be/SKRYhtBuCYE
Amazon link: https://amzn.to/2NH5q3n
Fuel cell: https://amzn.to/2NHW0Vp