The 2 pk of filters give you an ample supply to keep your humidifier functioning properly, ensuring clean and deodorized air in your home. Sunbeam SF221PDQ-UM Humidifier Filter, 2pk: * Contains antimicrobial product additive for built-in protection * Inhibits the growth of bacteria, mold and mildew * Features Arm & Hammer Baking Soda to naturally deodorize the air * Installs easily * For use with: Holmes HM3500, HM3501, HM3600, HM3640, HM3641, HM3650, HM3655, HM3655BF, HM3656, HM3656BF, Sunbeam SCM3501, SCM3502, SCM3657, Honeywell HCM6009, White Westinghouse WWHM3300 and WWHM3600