No job is too dirty for the MSR Guardian Purifier. Originally built for the military, the Guardian is the most advanced portable water purifier system. Perfect for the backcountry or camping abroad when you know the water sources are guaranteed to be contaminated. The Guardian will easily remove viruses, bacteria, protozoa and sediment from the nastiest water sources. The pump system is easy to use and will generate about 2.5 liters per minute. No need to clean or change the filters, this system has a self-clean feature built into every pump stroke without any chance of back-flushing or accidental contamination. This pump is extremely durable and will pretty much withstand any conditions. Perfect for the global traveler or trekker, and an absolute must for any emergency kit. The Guardian made its debut in 2015 and is finally available for purchase at multiple locations.