The Duux humidifiers help keep the humidity in your home at the right level. There are 3 different variants of Duux humidifiers to choose from, each with a different method of humidifying. The Duux ultrasonic humidifier transmits a thin mist by means of vibrations underwater, for example. A cool mist humidifier moves the air across a wet element, which provides natural humidifying. And if you want to purify the air in addition to humidifying it, choose a Duux air washer.