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-percent Of bacteria, 99.99-percent Of protozoa, and 99.999-percent Of viruses. The larger capacity of the mission filter is ideal for providing clean water to groups. Hang it at base camp for your next backpacking, boating, or car camping trip. To use, simply fill the reservoir with the cleanest water available, fold the top to seal and hang the mission from a 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 fibres, 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 and is easily filled with source water from a stream or lake. Shoulder carrying strap makes it convenient to travel back to campsite. Includes drawstring stuff-sack for easy storage and carrying. Includes four extra pre-filter screens for easy on-site maintenance. Produces flow-rate of 9-12 litres (2.4-3.2 Gallons) per hour and will purify 18,000 liters over its lifetime. Available in 5 or 12 litre sizes. Weight: 13-ounce (5l), 15-ounce (12l). For each LifeStraw product sold, one school child in a developing country will be provided with safe drinking water for an entire school year.