The Airome 100 mL Medium Ultrasonic Essential Oil Diffuser works by using slight vibrations to emit a fine mist of cool water to carry your favorite essential oil. All of our Airome products are made using quality materials of ceramic, porcelain, glass, and metal. The medium 100 mL diffuser allows you to enjoy a mist of essential oils for up to 8 hours. From traditional and classic to modern and geometric, we've created a variety of styles for your every mood and decor. Your choice of two settings of intermittent which will run for 8 hours, or continuous which runs for 4 hours. Our woodgrain diffuser automatically shuts off when the water runs out.