The Baby Ultrasonic Cool Mist Humidifier provides up to 24 hours of soothing, comfortable moisture per filling, with adjustable mist control, on/off nightlight and automatic shutoff when the tank is empty. Ultrasonic technology is whisper quiet, so it’s ideal for small to medium bedrooms or baby rooms. The large 1-gallon tank is easy to remove and fill, and features anti-microbial technology that prevents the growth of molds and mildew on the surface of the water tank. Includes demineralization cartridge to prevent the release of minerals (and white dust) into the air.