Filter K Household Odor/Gas Reducing Pre-Filters assist in capturing harmful and potentially dangerous gasses and VOCs such as ammonia from the air that pass through the filter. It traps larger particles such as dust, lint, fibers and pet fur. Filters perform as deodorizers, keeping your surrounding area smelling fresh and clean. They are compatible with Honeywell HFD-120, HFD-123, HFD-140, HFD-230, HFD-280, HFD-300, HFD-310, HFD-323 and HFD-360 air purifiers to establish an unrivaled breathing experience. These pre-filters are also a helpful addition to the ifD filter used in Honeywell QuietClean and AirGenius Air Purifiers. Filters trap larger particles before they reach the ifD filter.