This Web-Tex survival canteen works immediately and is simple to use. Proven technology capable of 1600 litres of natural tasting safe drinking water free of contaminants from any source. Light yet robust, the Web-tex surviva-pure system has built-in purification and post purification filtration that destroys and removes Cryptosporidium Giardia, Anthrax and many more harmful bacteria. Uses absolute 2.0 micron filtration with tortuous path technology for maximum effectiveness. 0.8 liter capacity.