Honeywell HC-835 Replacement Filter for Robitussin and Vicks Cool Moisture Humidifiers Fits models: Robitussin: DH-835, Vicks: V3500 Removes minerals and pollutants from water ProTec Antimicrobial helps prevent growth of mold, fungus, algae & other bacteria on filter Reinforced for maximum efficiency and longer filter life Exclusive Dry Lift Handle helps to keep hands dry and clean