The DuPont Standard HEPA Filter combines HEPA with activated carbon and a separate washable prefilter to effectively capture microscopic particles, allergens, volatile organic components and odorous gases. 360-degree filtration draws in air from all directions to collect pollutants from around the room that may affect allergy and symptoms. Washable prefilter offers the first level of defense against dust and pet hair. HEPA filter removes pollutants as small as 0.3 microns. Air filter is compatible with all TruSens Medium Air Purifiers (sold separately).