The nano positive filter cartridge is designed for the 4Swiss WFF021 home water filter system. The 0.01-0.001㎛ NF membrane removes heavy metals, chlorine and volatile organic compounds (VOCs) as well as 99.99 % of viruses and bacteria (E. coli, Staphylococcus aureus, Pseudomonas aeruginosa). Changed every 12 months (at 10 litres of water per day) or every 3600 litres.