MSR MiniWorks EX Water Purifier System - Get added viral protection that's critical in popular wilderness areas and developing countries with this comprehensive purifier and microfilter system. The MiniWorks Microfilter, the best-selling filter for demanding conditions, utilizes a ceramic/carbon element to filter out waterborne bacteria and protozoa, as well as particulate, taste and odors at 1 liter per minute. The MiniWorks EX Water Purifier System provides the most reliable water possible in a compact, lightweight system that's great for backpacking and international travel. This system meets U.S. EPA requirements for microbiological water purifiers. Features Effective Against: Viruses (99.99%), bacteria (99.9999%), protozoa (99.9%) and particulate. Meets U.S. EPA drinking water standards and NSF protocol P231 testing standard. Reliable: Filter's durable ceramic/carbon element ensures safe, taste-free water-even with frequent, heavy use. Field-maintainable: Filter can be cleaned repeatedly for full flow recovery with no tools required.