Exceeds MOD Specification - Tried & tested by special forces worldwide! Just fill from absolutely any water source & drink immediatley. New all in one water purification filtration system Works immediately - simple to use - no pumps Proven technology capable of up to 1600 litres (200 litres for the straw) 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 Cyptosporidium Giardia, Anthrax and many more harmful bacteria Uses absolute 2.0 micron filtration with tortuous path technology for maximum effectiveness