Highest volume water bottle purifier. Ideal for backpacking and trekking. EPA registered to remove all types of microorganisms, including viruses. 1 Liter bottle size provides extended range water capacity. Purification method: Virustat Technology plus microfiltration and carbon. Bottle capacity: 34 oz. Cartridge capacity: Up to 26 gal. Weight: 8 oz. Height: 11". Virustat kit is the complete filter element. Cyst filter is only the first stage of the Virustat filter. Replace Cyst filter when flow is restricted.