Compatibility with IQAir HealthPro Air Purifiers: Filter-Monster replacement filter bundle compatible with IQAir PreMax, V-5 Cell and filters. Engineered to be compatible with IQAir HealthPro Series air purifiers. Replacement air filter compatible with the filter uses filtration to remove up to 99.97% of airborne particles as small as 0.3 microns. Recommended to replace every 4 years for maximum efficiency. V5-Cell Compatibility: Replacement air filter compatible with the V5-Cell filter uses activated carbon to reduce VOCs (volatile organic compounds) and other harmful chemicals. Recommended to replace every 2 years for maximum efficiency. PreMax Compatibility: Replacement air filter compatible with the PreMax pre-filter extends life of V5-Cell and filters by capturing coarse and fine particles. Recommended to replace every 18 months for maximum efficiency. Set of 3: Each bundle comes as a set of (3) replacement filters. Filter-Monster branded replacement filter bundle compatible with IQAir HealthPro Series air purifier removes smoke, dust, pollen, pet dander, mold spores and dust mite debris from the air.