The Sharper Image MIST 4 ultrasonic humidifier is simple to use with easy touch controls that feature two cool mist settingsand a 360° rotatable mist nozzle. The MIST 4 has a 0.66 gallon capacity with 1.4 gallon daily output, and it includes an auto-shutoff feature to conserve energy when the water tank empties. When it is empty, refills are a breeze. Simply remove the top and fill it right up. The MIST 4 is a sleek addition to any space with a 1-year warranty.