Filter cartridge is filled with ion exchange water softening media. The chemical process of exchanging ions of calcium and magnesium into ions of sodium eliminates water hardness. Water with high content of ions of calcium and magnesium minerals (so called hard water) causes sink stains and damages home appliances such as: tea kettle, dishwasher and washing machine, and increases their energy consumption. Size: 10', Filter life (months): 3-6.