Replacement filter is designed for Fellowes AeraMax 190 Air Purifiers. The True HEPA Filter captures 99.97 percent of airborne particles as small as 0.3 microns, including pollen, ragweed and other allergens, viruses, germs, dust mites, mold spores and odors. AeraSafe antimicrobial treatment provides built-in protection from the growth of odor-causing bacteria, mildew and fungi on the True HEPA filter. The filter should be changed once a year. 4 per package.