This sleek, compact design of the HealthSmart 40-682-000 is perfect for your nightstand and desk. The ultrasonic cool mist humidifier is great for travel since it is small and portable. It has an aroma function ability to add essential oils and great for spa feeling in the privacy of your home. It has a mist regulation knob, quiet operation, auto shut off at minimum fill level. Run time up to 3 hours and holds up to .11 gallons of water. Removable power cord ideal for portability. Filter-free design with refill indicator light.