EC VISION Ceramic Ultrasonic Aromatherapy Diffuser/Essential Oil Purifier Diffuser Air Humidifier(Black) Ultrasonic vapor diffusing keeps the original effect of essential oils instead of heating or burning them which may destroy their original molecular structure Ultrasonic transducer vibrating at a frequency of 2.4 million times per second makes the molecule of water and essential oils so tiny that it is easily absorbed by our body Features a simple & elegant design while it delivers the aromatic luxury feel to your home. Safe auto-off at low water level. Two switching operation modes to choose the diffusing duration