Increase air moisture in your bedroom, nursery, or office for comfort with the 3/4 gal. Ultrasonic Cool Mist Humidifier. Customize your air quality with the humidifier’s 3/4 gal. water tank capacity, cool mist feature, and manual humidity control, along with power-on and refill indicator lights. When the reservoir is empty, the tank’s automatic shut-off function will conveniently kick in to save you the hassle of having to turn the machine off yourself. This whisper-quiet cool mist humidifier can be used while you sleep, while you take work calls, or while you're watching a movie without interrupting.