FEATURES: 1. Ultimate Virus Protection: Meets NSF protocol P248 military testing standard for removing viruses (99.99%), bacteria (99.9999%), protozoa (99.9%), sediment and microplastics from “worst-case” water conditions. 2. Better-Tasting Water: Two-stage purifier includes activated carbon to reduce chemicals and unpleasant tastes and odors. 3. Easy to Fill: 10 -liter reservoir is easy to fill at sinks and streams alike; covers daily water needs for drinking, cooking and hygiene. 4. Simple Cleaning: No backflushing required—simply opening the purge hose flushes the system to clean it and maintain flow rate. 5. Fast-Flow Rate: Up to 1 liter in 2 minutes with optimal reservoir hang height of 6 feet, 2.5x faster than the next leading gravity purifier. 6.Engineered for Travel: Rugged, military-grade construction. Compact system fits easily in carry-on luggage and smaller packs. 7. NSF P248 Testing Standard: The most rigorous scientific certification for proving a treatment device safely removes claimed contaminants from challenging wilderness water sources. Guardian devices are the market’s only purifiers to pass the military standard P248 testing for virus removal.