Enjoy the crisp cool H2O of a mountain stream while guarding against particles, protozoa and bacteria like Giardia, salmonella and cryptosporidium with the Klean Kanteen Classic H2O Filter Adapter. These small, lightweight H2O filter adapters feature one end that screws into Klean Kanteen Classic bottles while the other end has a universal thread design that connects to most standard backcountry H2O filters. Get your H2O straight from the source with the Klean Kanteen Classic H2O Filter Adapter.