The Honeywell Household Odor & VOC Reducing Pre-Filter (2 PK) deodorizes the air with potassium permanganate calcite. It helps capture certain harmful gases/VOC?s such as fumes from cleaning products paint and furnishings. 1)Helps reduce common household odors such as odors from cooking smoke pets bathrooms nurseries and kitchens 2) Helps capture larger airborne particles such as dust lint fibers pet hair & fur maximizing the HEPA filter life 3) For best performance replace every 3 months 4) Fits Honeywell model series: HFD-120 HFD140 HFD230 HD123 HFD280 HFD300 HFD310 HFD320 HFD360.