Filter Compatibility: Compatible with Honeywell HRF-C1 and HRF-C2 air filters. Model Compatibility: Replacement filters are compatible with Honeywell air purifier models 16200, HHT-011, HHT-080, HHT-081, HHT-085, HHT-090, HHT-145, and HHT-149. Air Quality Improvement: Filtration is rated H13 and removes up to 99.97% of airborne particles as small as 0.3 microns in size including dust, smoke, pollen, pet hair and dander, mold spores and dust mites. Maintenance: Recommended to change this filter once every six (6) months under normal conditions, and more often under harsh air conditions. Multipack: Each package contains two (2) replacement filters. Filter-Monster branded compatible with Honeywell C Filter (HRF-C1) removes smoke, dust, pollen, pet dander, mold spores, and dust mite debris from the air.