ULTRASONIC COOL MIST TECHNOLOGY: Safely moisturizes the air for up to 16 hours of continuous operation so you can breathe easy and get more restful sleep | High and low speed settings make it easy to adjust mist direction and speed to fit your comfort levelEven a large room or office (on the high mist setting) will be full of fresh and clean air for 12 hours.OPTIONAL NIGHT LIGHT: Offers soothing glow for maximum relaxationAUTOMATIC SHUT-OFF: Turns humidifier off when water level is low or the water tank is removed