A whisper-quiet design with an on/off night-light function allows for easy use at night. Diffuse your favorite essential oil with the actual oil tray and included pads. Clean Tank Technology helps protect the tank from unwanted build-up. The Homedics Total Comfort Ultrasonic technology converts water into a fine mist that is dispersed evenly into the air; adds the perfect amount of moisture to any large bedroom or family room up to 426 sq. ft. Top-Fill Tank for ease of use and features a 1.47-gallon tank that provides up to 70 hours of runtime per fill. A demineralization cartridge is included to help prevent buildup from hard water. As a safety feature the humidifier automatically shuts off when the tank is empty.