The Honeywell Replacement HEPA Air Purifier F Filter is certified to help capture up to 99.97% of the following microscopic airborne allergens and particles as small as 0.3 microns: dust pollen pet dander dust mite debris and smoke. Compatible with: 17200 / 13520 / 50250 / 18150 / EV-10 Series In the Box: 1 F HEPA Filter For best performance use only Genuine Honeywell air purifier filters. Replace filter every 1-5 years depending on use.