Intended for emergency use, the SeaPack produces a life-saving drink directly from seawater. Perfect for use on your off- shore boat, sea kayak or for use in your life raft. The filtered drink is very similar to the juice from pressed grapes and provides 480 calories from each half liter of an important energy source during emergencies. The tight osmotic membrane rejects a full 97% of the salt. Because the SeaPack is passive, there is no pumping involved. This is obviously an advantage if the user has been injured or exhausted and would have difficulty operating a pump-style system.