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 1.5-liter tank capacity provides ideal coverage for bedrooms, offices, and other medium-sized rooms 360-degree mist nozzle and dual-speed control make it easy to adjust mist direction and speed to fit your comfort level Automatic shut-off safely turns humidifier off when water level is low or the water tank is removed Optional night light offers soothing glow for maximum relaxation