Everpure EV9607-10 ESO 6 Cartridge Unique three stage blending cartridge provides softened/buffered/filtered water Small amount of carbon filtered water bypasses softening resin to allow proper initial hardness. Buffering prevents water from becoming too acidic Reduces hardness in water that can cause minerals to build-up in coffee and espresso equipment 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