The Guardian Purifier Pump Water Filter from MSR is designed to provide safe water purification anywhere in the world. Advanced hollow fiber filter cartridges meet the strict testing standards of the U.S. military for removing viruses, protozoa, and bacteria, as well as sediments from dirty water. With each pump stroke, the system cleans itself. The Guardian Purifier Pump Water Filter can purify two and a half liters of water per minute—completely without batteries or chemicals. Overall, the water filter can purify up to 10,000 liters of water. MSR has equipped it with a durable construction that withstands extreme weather conditions and impacts.