Designed for Honeywell HCM-750 Series for cool moisture humidifiers, the HAC-700 Replacement Filter B removes minerals and pollutants from water. Air Washing Prefilter helps capture dirt, dust and pollen from the air that passes through the filter. Protec Antimicrobial Treatment helps prevent the growth and migration of mold, fungus, algae and bacteria on the filter. The filter material is reinforced for maximum efficiency and longer filter life.