HRF-B1 For optimal performance, replace the HRF-B1 filter every 3 months. It helps absorb some common household gases and fumes. The Honeywell/Kaz Household Odor & Gas Reducing Pre-filter, model HRF-B1, uses activated carbon and zeolite 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-B1 includes one pre-filter.