Everpure EV9607-25 ESO 7 Cartridge Utilizes ion exchange resin with buffering capabilities and high capacity coconut carbon filtration Small amount of carbon filtered water bypasses softening resin to allow proper initial hardness Buffering prevents water from becoming too acidic Reduces minerals such as calcium and magnesium. Reduces chlorine, off tastes and odors Sanitary cartridge replacement is simple, quick and clean. Internal filter parts are never exposed to handling or contamination