Having clean drinking water is a must while backpacking or traveling, which means you need this Grayl UltraPress Replacement Purifier Cartridge to replace the old one in your Grayl® Purifier bottle. Made to remove waterborne pathogens and absorb dangerous particles, this cartridge restores your ability to have the cleanest water possible no matter where you are in the world. Don't be sidetracked because of harmful bacteria in the water. Instead, continue exploring the amazing world around you knowing you always have fresh water available at all times.