This essential oil diffuser/humidifier looks like a candle when operating with the ambient light turned on. It has a 280mL capacity tank and operates via USB. It is 11.5cm high and delivers 35mL/hr fog. To use simply fill the reservoir with water and add a couple of drops of essential oil. Plug in the USB. Press once to turn the humidifier on or off and press for 3 seconds to turn the ambient light on or off. Every diffuser is supplied with 1 x 15mL pure essential oil of your choice.