Genuine Advanced HEPA+ Replacement Filter Pack replaces all filters that come with the Advanced HEPA+ Air Purifier. Filter pack includes the main filter assembly, consisting of a True Medical‐Grade HEPA filter, activated carbon‐zeolite filter, and medium‐particle pre‐filter, plus the large‐particle outer pre‐filter. These filters work in 4 progressive stages to remove 99.97% of allergens and other particles, plus odors, smoke and gases from indoor air. Package contains one (1) complete filter pack. The Replacement Genuine Advanced HEPA+ Filter Pack includes all filters that come with the Advanced HEPA+ Air Purifier.