Sunbeam SF221PDQ-UM Cool Mist Filter D Contains antimicrobial product additive for built-in protection Sunbeam humidifier filter inhibits the growth of bacteria, mold and mildew 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 Features Arm & Hammer baking soda to naturally deodorize the air Important for proper humidifier operation