HRF-K2 Kaz Inc. - Honeywell The Honeywell/Kaz Household Odor & Gas Reducing Pre-filter, model HRF-K2, uses potassium permanganate calcite to capture odors and freshen the air. It's also a particle filter, designed to capture larger particles like dust, lint, and pet fur.
HRF-B2 includes two pre-filters. It helps absorb some common household VOC gases and fumes. For optimal performance, replace the HRF-K2 filter every 3 months.