ENERGY EFFICIENT: This energy-efficient Holmes ultrasonic humidifier propels visible, cool mist, with a virtually silent, filter-free operation15-HOUR RUNTIME: This Holmes humidifier has a 0.33-gallon water tank capacity with a 15-hour run time on a full tank and low settingIDEAL FOR SMALL ROOMS, COMPACT SIZE: Ideal for small rooms, plus its compact size allows for portability within the homePREVENTS MOLD AND BACTERIA: Includes an antimicrobial protective material in the water tank to prevent mold and bacteria growth that can cause stains and odors or adversely affect performanceCUSTOMIZABLE SETTINGS: Features an easy-to-use, one-touch button to switch between 2 speed settingsADJUST YOUR MIST DIRECTION: Contains a rotating mist nozzle to adjust your desired mist directionWATER SHORTAGE INDICATOR LIGHT: Features a water shortage indicator light to let you know when it's time to refill your tank