The Greenleaf Aroma Diffuser uses ultrasonic technology to instantly vaporize water and essential oil to product a cool, dry fragrant mist. The amount and intensity of the mist produced will vary die to water type, humidity, temperature, and air currents. The unit will not work without water. Only Greenleaf pure essential oils should be used in this product. Use 2-3 drops per 100mL water at a time.