For Hunter HEPAtech Air Purifiers. Fits Models: 30200, 30250, 37255, 30375, 37375, 30380. Permanently "charged" HEPAtech® filter captures particles as small as 0.1 microns in size. Captures allergy causing smoke, pollen, dust, mold spores, pet dander, and other irritating allergens. Lasts up to 6 months under continuous use. 99.97% Effective Air Cleaning . From the Hunter Fan people...quietly improving your indoor air since 1886. *Based on the AHAM/ANSI AC-1 Test. Results may vary based on user s environment and intended room of use.