This little thing is a great idea. A tiny, under 2oz solar charger that can charge cell phones or mp3 players in a pinch. It can also be charged via USB. Perfect for the traveling person. If it actually worked. Mine has never taken a solar charge, even after a week in bright California sunlight. I was never able to get a response from the maker of the unit. I'd give it 10/10 for the idea and 1/10 for actual use, since it doesn't actually work.