The MSR Guardian Purifier is touted as the world’s most advanced portable purifier. First off, the Guardian is super fast. It puts out 2.5L per minute which is equivalent to 2 and half Nalgene bottles in just 60 seconds! That alone sold us on this purifier. Another feature that sets the Guardian apart is the revolutionary self cleaning on every stroke, which means you will NEVER need to backflush or scrub the filter. The life of the filter is another impressive feature. The Guardian will filter 10,000 + liters of water which is equivalent to 9600 Nalgene bottles. Finally, the Guardian has you completely protected removing viruses, bacteria, protozoa, and particulates from water. If you are not quite convinced that the Guardian is a game changer just watch the attached video.