Genuine OEM Hunter replacement air filter 30915 for Hunter HEPAtech air purifiers. 99.97% effective air cleaning. Captures smoke, pollen, dust, mold spores, pet hair and dander - plus bacteria and other irritating allergens. Three stage filter: 1. Mesh particle screen prefilter captures larger particles such as dust, lint and hair. 2. Submicron primary filter is made out of a micro-filter material which removes particles as small as 0.1 microns in size. 3. Activated charcoal filter removes odors. Fits Models Hunter HEPAtech Air Purifiers: 30010, 30025, 30040, 37025 Replace every 4 to 6 months The need to change a filter depends on where and how the air purifier is used and the rate of new particle introduction into the room environment. The replacement filters for Hunters HEPAtech models are designed to last 4 to 6 months under constant use. Back of filter contains built-in activated carbon for odor control.