Humidifier holds 1 gallon of water and produces up to 2.3 gallon moisture output per day;Provides relief from cough, cold and flu symptoms;Increases air moisture for easier breathing and a good night's sleep;Whisper-quite ultrasonic operation runs up to 24 hours;360 degree mist nozzle and variable control settings;Auto shutoff safety sensor;Increases air moisture for easier breathing and relieve of cough, cold, and flu symptoms, including nasal congestion, dry cough, sinus irritation, nose bleeds as well as dry skin;Ultrasonic cool mist operation does not require a filter to run (demineralization filter available - model # HS-3161);1 gallon water tank runs whisper quiet up to 24 hours. To fill, simply remove the drop shape water tank from the unit, unscrew the tank cap, and fill the tank under the water faucet;Puts out up to 2.3 gallons of moisture per day and effectively humidifies rooms up to 250 square feet;Auto shutoff safety sensor and 360 degree output nozzle