The diffusion, which produces vibrations at a frequency of 2.4 million times per second, dissolves water and essential oils into extremely fine microparticles without using heat (heat alters and destroys the properties of essential oils). The ULTRASONIC diffusion feature ensures the integrity of the beneficial molecular structure of essential oils and allows for easy healthy bodily absorption. Large 500 ml water capacity that can continue to be used for up to 18 hours at a time. When the time is up or there is no water, it will automatically shut off. Press the "Mist" button, select the timer from 60 minutes, 120 minutes, 180 minutes, or ON. Improve air quality and avoid allergens and unpleasant odors such as smoke. It works as an ionizer by releasing negative ions into the air that combat harmful positive ions. This provides many health benefits, such as improving breathing, boosting the immune system, helping to alleviate mood and relieve stress. It helps to clean and humidify the air and improves the quality of the air we breathe. The unit can also be used as a humidifier without aromatherapy. It provides moisture for dry cough, dry skin.