The Filter is the ideal choice for allergy sufferers and other health-conscious individuals that need high-efficiency particle removal. The filter is one polypropylene 3-stage progressive filter that contains millions of ultra-thin fibers with each state trapping progressively smaller harmful particles as they pass through the pleats. The filter 3-stage progressive filter effectively removes every type of particulate air pollutants, including allergens, pollen, mold spores, dust, pet dander, bacteria, and viruses. Designed to fit Blueair 200 series. This is not a genuine product. Compatible with blue air 200/300 Series, Classic 203, 270E, 303, 201, 250E, 215B, 210B, 205 Aftermarket filter and one filter can last from 6 months to a year based on normal use or dependent on usage HEPA Air Purifier Filters Compatible with 200/300 Series Particle Filters Designed to fit Blueair 200 series Captures 99.97% of harmful particles such as dust, pollen, and smoke down to 0.1 microns in size. Gradient filter structure resists clogging for maximum airflow, never re-releasing harmful particles