The way we see it, a water filter is a simple concept: you put nasty water in, and tasty water comes out. So when they say that it works in 120 countries, we were a bit confused. But when you think of how nasty water gets in third world countries, it makes sense. ÖKO uses NASA derived filtration technology to provide different filters that are dependent on the country’s water. L.A. water might be gross, but Somalia’s has to be worse. Bottle starts at $22.95.