Cool alternative technology that is providing inexpensive lighting for those millions of people that are off-grid (targeting Africa at the moment). Remember clocks that used to work using weights? Here's a light source that uses weighted bags to run and LED or two.
I think it's great that someone did the R&D toward a commercial model. I also applaud that these gizmos were initially intended for use in Africa (or parts of the world with similar nighttime lighting challenges). At least one factory has been set up in Africa for them, and it could be many factories for all I know.
But I haven't found a source for this model GL02—made in Africa, so far as I know—that sells in North America for under a hundred bucks! So what's with that? It may be to provide funds to support the third-world production facilities... but why not sell the unit for half that price (or less), thereby making them more appealing and sell many more?