I was at a "preparedness" conference today and saw something cool at a vendor booth. Shaska Products If it in fact does all it says, it would be a good addition to a BOB because of its size (about the length of two Bic pens laid end-to-end and about as round). I don't think I would use it to replace a Berkey system or hiker-type filter. From talking with the lady who distributes them, seems to be a fairly new technology and they are looking for distributors and retailers across the U.S. Someone should send a few to Les Stroud and let him try it out.