Designed for small rooms, this 0.6-gallon humidifier has adjustable mist control to regulate the humidity level. The humidifier can operate for up to 24 hours on the lowest setting and automatically shuts off when the tank is empty. This Vicks Cool Mist Humidifier utilizes Ultrasonic Technology for whisper-quiet operation that will not disturb sleep and it has an optional color-changing nightlight. Cycle through the 7 colors or stop on your favorite - it is up to you. The 3-in-1 is easy to operate, with no filters to replace. Provide the comforting scent of Vicks anytime by adding a Vicks VapoPad or your favorite essential oil.