The MSR Guardian Water Purifier Pump was originally designed for the U.S. Military, who turned to MSR’s advanced water filtration technology to keep troops safe and healthy in every remote corner of the globe. Six years of research and development went into engineering the pump purifier, which removes viruses (such as norovirus, rotavirus, hepatitis A), bacteria (such as E. coli. Shigella, salmonella, cholera), protozoa (such as giardia, cryptosporidium, amoebae), and sediment from contaminated water sources anywhere on earth. It meets the strict NSF protocol P248 testing standard for the U.S. Military, using medical-grade fibers to provide protection from the tiniest microbiological waterborne threats. Designed to be fast, simple, and safe, it pumps at a rapid 2.5 liters per minute, has a long-lasting advanced filter that treats up to 10,000 liters of water, and withstands freezing temperatures, drops, heavy use, and harsh environments. A self-cleaning mechanism ensures reliability, flushing contaminants in the filter back into the source, so there is no backflushing or scrubbing cartridges to maintain flow. The MSR Guardian Water Purifier Pump is ideal for wilderness, backcountry use, expeditions, global travel, and emergency preparedness. It measures 8.2 x 4.7 inches and weights 17.3 ounces. Made in the USA.