It’s quite interesting technology. A box with a plastic strip passing through it… on one end of the box a bag with 1 kilo of stones in, on the other a bag with 10 kilo stones. The bigger bag pulls through the strip, which powers a LED light!
This was sitting in the shed for 6 months or more, we couldn’t decide where to put it and then i just decided to try a hook in the kitchen and now there’s a weak light to brush teeth by. Better than the strong LED light that is hooked up, that seems to be too bright last thing.