Humidifier adds cool mist to the dry air in spaces of up to 350 sq. ft. to help create a comfortable environment to breathe Ultrasonic technology disperses mist silently to add moisture to dry air Top-fill design makes it easy to add or remove water without creating a mess while flash warning lets you know water is running low Three-speed mist control and 12-hour timer offer customisable convenience Sleep mode sets the device to the lowest speed and turns lights off for minimal disturbance