The Platypus GravityWorks High-Capacity Water Filtration System is ideal for basecamps, group and family camping, outdoor activities, and emergency preparedness. It does not require pumps, batteries, moving parts, or chemicals, ensuring access to clean water from contaminated sources, in situations ranging from adventure to survival. The replaceable hollow-fiber microfilter cartridge filters up to 1,500 gallons of water, and meets all EPA and NSF guidelines for water filtration. The water filtration system is easy to use almost anywhere. Simply scoop water from a lake, river, stream, or other contaminated water source into the dirty water reservoir and suspend above the clean water reservoir. Water flows through the walls of the bundled fibers at rate of 1.75 liters/minute, leaving impurities behind, and filling the clean water reservoir in a matter of minutes. It’s also easy to maintain in the field, backflushing in just four seconds to clean and restore performance. The Platypus GravityWorks High-Capacity Water Filtration System includes a dirty water reservoir, clean water reservoir, hollow-fiber microfilter, hoses, shutoff clamp, and storage sack. Available in two sizes: The 6.0 Liter configuration weighs 12.5 ounces and includes reservoirs with a 6.0 Liter capacity each, and the 4.0 Liter configuration weighs 11.5 ounces and includes reservoirs with a 4.0 Liter capacity each. Each complete kit is compact, packing down to the size of a one-liter water bottle. Manufacturer's limited lifetime warranty. Made in the USA.