Platypus GravityWorks Water Filter System

What's the easiest way to filter water? Let gravity do all the work. Just fill the dirty water reservoir, hang it from a tree, and gravity will push the water through the hollow-fiber filter for instantly clean water. Collecting water from the lake or river is easy, too. Simply open the wide Big Zip(TM) opening, scoop up water, and close the reservoir. Then open the hose clamp to control the water's flow into the clean water reservoir. The system is field cleanable, too. Simply backflush the water by raising the clean water reservoir higher than the dirty reservoir to force water, and air bubbles, back into the dirty water reservoir. Meets EPA and NSF guidelines for removing bacteria and protozoa, including Giardia, Cryptosporidium, E. coli, Salmonella and Cholera. Let gravity do the hard work; no pumping required Removes bacteria and protozoa, including Giardia, E. coli, Cryptosporidium, Salmonella and Cholera Lightweight, compact system stows smaller than most 1L bottles Field-cleanable microfilter is easily backflushed in 4 seconds to maintain performance Hundreds of tiny hollow fibers filter water faster than traditional filter media Microfilter lifetime of up to 1,500 liters of water Big Zip(TM) opening for easy water collecting and dispensing Meets EPA and NSF filtration guidelines 2L model makes it easy to treat water for 2-4 people 4L model easily supplies water for larger groups 2L model includes: 2L Platy(TM) bottle, 2L dirty reservoir, hollow fiber microfilter, universal bottle adapter, push/pull cap adapter, hoses, and storage sack 4L model includes: 4L clean reservoir, 4L dirty reservoir, hollow fiber microfilter, hoses, shutoff clamp, and storage sack