It is actually a FORWARD osmosis system, hence the sugar solution being required, and no water pressure. They say it will make a drink from a toxic mud puddle. This seems to be the major advantage of this system.

Check out the FAQ area of their web site. It appears that it will filter out slightly salty water and have been used for urine even. <img src="/images/graemlins/shocked.gif" alt="" />

They are working on a syrup solution which will allow them to be used for salt water. The shelf life is actually longer than 3 years and longer if cooler.

This one is a camel back type unit and is much cheaper at $64
x pack (camel back style)