Cool Moisture Humidifier helps temporarily relieve dry air discomforts for better comfort for medium-size rooms. UV technology kills up to 99.9 percent of certain bacteria, mold, fungus and virus in the water after two hours of continuous use. This design provides the assurance that the moisture emitted from the unit is virtually free of germs. Self-regulating Evaporative System adjusts output to the amount of moisture the air can hold at a particular temperature. Durable break-resistant water tank along with the tray is dishwasher-safe. Design also includes a Protec Antimicrobially Treated Filter. Humidifier runs up to 24 hours per filling.