Holmes "E" Humidifier Filter 3 Pack, HWF100-UC3 Improves efficiency of the humidifier Extended filter life with help of reinforce outer layer Extends product life as less mineral deposits will attach to the unit Install at the beginning of each season, replacing every 2 to 4 weeks or as needed Works with models HM630, SCM630, BCM646, HM7808, SCM7808, BCM7205, HCM730, BCM7305, HCM729G