This ultrasonic essential oil diffuser vibrates the essential oil with the distilled water to create a powerful plume of aromatherapy mist delivered to your space. With a ceramic shell, this diffuser has two settings, a thirty second on and off, or a continuous stream. Depending on the setting, it runs 4-8 hours and shuts its self off when water is gone. Using only distilled water, this ultrasonic diffuser is easy to clean and care for. There is a small light at the base that adds to the subtle ambiance of this soothing and relaxing mist. 8" tall and 3 3/4" wide. (Only use essential oils in this diffuser along with distilled water.)