Crane Drop Cool Mist Humidifier Orchid & White Ultrasonic Cool Mist increases air moisture for easier breathing and a good night's sleep Increases air moisture for easier breathing Whisper-quiet ultrasonic operation runs up to 24 hours Puts out up to 2.3 gallons of moisture per day and effectively humidifies rooms up to 250 square fee Auto-Off function activates when water tank is empty