BWT 3-Pack Long Life Mg2+ Cartridge for Water Filters, 120-Liter Capacity 3 cartridges = 3 months or 360L ( 120L per month) Mineralized drinking water - filtered water with the flavor carrier Magnesium which provides AROMA, CLARITY and FLAVOUR Saves money, spend less on bottled water, protects the environment Protects kettles and coffee machines from Lime scale Quick filtering less waiting time