The LifeStraw Mission is a gravity-powered water purifier employing an award-winning technology that requires no chemicals, batteries or moving parts. The LifeStraw Mission removes 99.9999% of bacteria, 99.99% of protozoa, and 99.999% of viruses. The larger capacity of the Mission water purifier is ideal for providing clean water to multiple people, and is designed for camping, hunting, and other group or family activites, as well as disaster and emergency survival prep kits. The reservoir can be filled from nearby lakes, ponds, rivers, or streams and suspended from a tree or other sturdy support. Gravity moves water down the hose to the filter's advanced ultrafiltration membrane. Clean water exits through 0.02 micron pores in the walls of the hollow fibers, but bacteria, viruses, protozoa and other contaminants are trapped inside and are flushed out by backwashing. Compact, BPA-free roll bag reservoir features a wide mouth for easy filling with a convenient shoulder carrying strap for transport back to base camp or other group location. Includes drawstring stuff-sack for easy storage and portability. Includes four extra pre-filter screens for easy on-site maintenance. Produces flow-rate of 9-12 liters (2.4-3.2 gallons) per hour and will purify 18,000 liters over its lifetime. Available in 5 or 12 liter capacity. Weight: 13 oz (5L), 15 oz (12L). For each LifeStraw purchased, one child in a developing community receives safe drinking water for an entire school year