MSR Guardian Water PurifierFeatures: Military grade water purifier pump removes viruses, bacteria, protozoa, and particulate from contaminated water sources virtually anywhere on earth Meets NSF protocol P248 testing standard of the U. S. military, using medical grade fibers to provide protection from the tiniest waterborne threats Pumps at a rapid 2. 5 liters per minute, treats up to 10,000 liters of water, and withstands freezing, drops, heavy use, and harsh environments Pump