Replacement filters pack for the Osmio Zero Reverse Osmosis Water Filter System - change every 6 months. Filter contains: Quick-Change Sediment Filter 5µm: removes coarse particles, e.g. Sand, rust, chlorine, lime. Quick-Change activated carbon filter: removes chlorine and organic impurities. Quick-Change Membrane 50GPD: removes all pollutants and flavours to almost 100%. Quick-Change Insertion Filters: Hygiene After-filter antibacterial: removes 99% of the bacteria and viruses and improves the taste. The unit is designed to shut off if there is blockage in the membrane or prefilters. As the system recirculates the rejected water from the membrane, the Total Dissolved Solids (TDS) level continually rises of the water entering the membrane filter. Therefore, for those with water of higher TDS, more frequent carbon block and membrane changes are likely. It is recommended to have at least a spare carbon filter and membrane on hand with the unit at all times. if you have a hardness level over 250 Calcium Carbonate then you may need to change the carbon block and membrane more frequently than every 6 months.