High-capacity, pump-free filtration for groups and basecamps. Delivering 4 liters of filtered water in just 2.5 minutes with no pumping, the GravityWorks 4.0L system is the easiest and fastest way to get filtered water in the backcountry. Ideal for bigger groups or basecamps, the system has an 8-liter total capacity, easily providing filtered water for drinking, washing up, cooking, and cleaning. No pumping: Just fill the dirty reservoir, hang it, and let gravity do the hard work. Fast: Filters up to 1.75 liters per minute; filter lifetime up to 1,500 liters of water. Ultralight & Compact: System weighs 10.75 oz. (305 g) and stows smaller than most 1L bottles. Group-ready: 8 liter (4.0L filtered + 4.0L dirty) total capacity easily supplies water for groups. Field-cleanable: Microfilter can be easily backflushed in 4 seconds to maintain filter performance. Hollow Fiber Advantage: Hundreds of tiny, hollow fibers, enable the microfilter to filter water faster than traditional filter media. Easy collecting & dispensing: Collecting water is easy-simply open the top, scoop water, and close; control delivery of filtered water with hose shutoff clamp. Comes with: 4.0L Dirty reservoir, 4.0L Clean reservoir, Hollow Fiber microfilter, hoses, shutoff clamp, and storage sack.