Biological and viral water purification filter. Gravity powered filter system requires no hand pumping. Includes 0.02 micron absolute water purifier, 4-liter nylon dirty water dispenser, 4-liter clean water vessel with high flow dispensing cap, drink tube and quick release hose adapter. Flow rate: 5 gallons in less than 12 minutes. Removes viruses, bacteria, and protozoa. Sawyer Viral Purification removes viruses mechanically at a 5.5 log -- 99.9997% -- rate, exceeding EPA and NSF recommendations. BPA-free.