1.Replacement WF2 filter compatible with Honeywell HCM-300T, HCM-315T, HCM-350, HCM-350B, HCM-630, HCM-631, HCM-645, HCM-650, HCM-710, HCM1000, HCM2000, HCM540 Series. Compatible with Honeywell HAC504 Filter A HAC 504 HAC-504 HAC-504AW HAC504V1 humidifier filters. 2.WF2 Filter for Vicks humidifier 3000 Series: V3100, V3500, V3500N, V3600, V3700, V3800, V3850, V3850JUV, V3900, V3900JUV, VEV320, VE4000, for Starry Night & for Vaporizer. Compatible with Sunbeam 1118, 1119, 1120, for Robitussin DH835, for ReliOn WA-8D, for Kaz 3020, for Enviracaire ECM-250i & ECM-500. Compare to Part # PWF2 3.WF2 humidifier filter replacement are made of a double layer of absorbent mesh paper that works with an aluminum foil layer to trap minerals and pollutants in the water and keep your humidifier maintaining its peak performance and improving your breathing comfort, sleeping, nasal congestion and dry skin. 4.For Vicks humidifier filter replacement feature a honeycomb pad design that ensure optimal performance for optimal moisture output, raising the humidity level in your home to 40% - 60%. Create a y and comfortable breathing environment.