Nothing is safer or easier to use for purifying the most demanding backcountry water sources than the Guardian purifier. Originally designed for military squads, it brings this highly advanced technology to global travelers, backcountry users, and those stocking emergency kits. Fast and easy to use, this pump purifier offers the added viral protection you need when traveling in developing nations and popular wilderness areas. Its advanced hollow fiber filter offers the most reliable way to purify even filthy water conditions. Add its long-lasting performance and revolutionary self-cleaning ease, and this may be the only treatment device you’ll ever need. Effective Against: Viruses (99.99%), bacteria (99.9999%), protozoa (99.9%) and particulate. Hollow fiber filter meets U.S. EPA drinking water standards* and NSF protocol P248, U.S. military testing standard. *U.S. EPA Guide Standard and Protocol for Testing Microbiological Purifiers. Fast & Easy: Pumps a rapid 2.5 liters per minute, offering added viral protection without the need for chemicals, bulbs, batteries, or waiting. Self-Cleaning: Pump self-cleans on every stroke, providing consistently fast flow rates with zero hassle—no backflushing or filter-scrubbing ever required. Long-Lasting: Leading-edge hollow fiber cartridge treats up to 10,000+ liters. Extremely Durable: Engineered to withstand heavy use, freezing, drops*, and harsh environments.