Product contains a four pack of premium 2022 upgraded for Blue Honeywell Blue Humidifier Filters for Filter A, HAC-504, HAC-504AW, and HAC504V1. The best wicking filters for Honeywell humidifiers.We m more→anufacture our filters by utilizing a special interweaving locking pattern in order to keep the filter rigid and upright, even when soaking wet. Our competitors don't do this and use cheaper manufacturing methods that leads to worse performance.Designed to fit the following for Honeywell Humidifier Models HCM350W, HCM-350, HCM350, HCM-350B, HCM350B, HCM-350W, HCM-350B-CST, HCM-300, HCM300, HCM-300T, HCM300T, HCM-305T, HCM305T, HCM-310T, HCM310T, HCM-315T, HCM315T, HCM305BCST, HCM-450B-CST, HCM450BCST,…