Compatible HRFK2 Honeywell HRF-K2 Household Odor & Gas Reducing Pre-filter (Filter K) - 2 Pack - For Air Purifier by Complete Filtration Services (CFS) HRF-K2 Household Odor & Gas Reducing Pre-filter (Filter K) - 2 Pack HRF-K2 Air Filters. Fits air purifier models: HFD-070, HFD-120, HFD-12-Q, HFD-12-TGT, HFD-123-HD, HFD300, HFD310, HFD314, HFD320, HFD323-TGT, HFD324. This is not a Honeywell® OEM product and is not covered under any Honeywell® manufacturer's warranty. The Honeywell® brand names and logos are the registered trademarks of their respective owners. Any use of the Honeywell® brand name or model designation for this product is made solely for purposes of demonstrating compatibility.