Few things are more essential to an outdoors adventure than a steady supply of clean drinking water. The Platypus GravityWorks Water Filter provides four liters of clean potable water in about two and half minutes. Reservoirs made from polyurethane/polyethylene. Treated with antibacterial Slime Guard. Includes two four-liter reservoirs, one for dirty water and one for clean. Filter removes giardia, salmonella, cryptosporidium and others bacteria down to 0.2 microns. Flow shuts off automatically when the hose is disconnected. Proprietary PlatyTM zip opening collects water easily. To maintain maximum flow, hold the dirty reservoir over the clean one. Made in the USA.