Sunbeam SFU003 Univ Humidifier Filter with Color Check 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 Simply cut to fit your Cool Mist Humidifier Includes Color Check, a purple color strip that turns red when it's time to change the filter