Electrolux PureOxygen Allergy 450 Ultra Allergen & Odor HEPA 5-Stage Filtration Air Cleaner / Air Purifier, Black Premium HEPA filtration absorbs 99.97% of dust and allergens from the air down to 0.3 microns in size Washable filter cartridge includes a premium HEPA filter, high deodorization filter and pre-filterall washable Cleancel treated carbon filter includes a coating of Cleancel - a chemical compound that impedes the growth of bacteria and molds Change filter indicator will automatically let the user know when it is time to replace the filters Replacement filters for this model are EL049 HEPA or EL051 Washable HEPA and EL050 Carbon or EL044 set