The original medifilter (cartridge) for the FQ Defender 4000 removes microbes, viruses and harmful substances from the air, with an efficiency of 99.99 % or 0.1 micron. Comparison reference: The HEPA industry standard achieves only 99.97 % to 0.3 microns. More than three times less than HEGA. You don’t need to replace the medifilter every year. An indicator on your device will indicate when it is required. Is smoking allowed in the room? In that case, the filter must be replaced every year. The carbon filter (wrap) for the defender increases the capture of air pollution indoors. Extremely efficient against odours & gases. It can be placed easily and quickly around the medifilter. The active carbon filter is activated when you open the package and install the filter. It’s best to replace it every six months. Included in this package: one medi-filter and two carbon filters. Ensure that you only use the original HMI filters.