Katadyn Exstream Water Purifier Bottle (Olive) 21-ounce-self-contained purifier bottle Delivers 160 refills (100 liters/26 gallons) per replaceable cartridge Virustat Technology plus microfiltration and carbon purification Prefilter removes sediments and elements that cause bad odor and taste Kills over 99.9999% of waterborne bacteria and over 99.99% of waterborne viruses