The present invention is directed to an alternative compact portable filtration device that can be used in remote locations and includes a single filtration cartridge that provides redundant filtration of the fluid (water). In particular, the device is a dual stage ultrafilter cartridge (apparatus) that...http://www.google.es/patents/US7534349?utm_source=gb-gplus-sharePatente US7534349 - Dual stage ultrafilter devices in the form of portable filter devices, shower devices, and hydration packs
Dual stage ultrafilter devices in the form of portable filter devices ...
