Genuine OEM Hunter replacement air filter 30928 for Hunter HEPAtech air purifiers.Fits ModelsHunter HEPAtech Air Purifiers: 30057 30059 30078 30079 30097 30124 30126 Permanently charged HEPAtech filter captures particles as small as 0.1 microns in size. 99.97% effective air cleaning. Captures smoke pollen dust mold spores pet dander and other irritating allergens. 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.