Among the many air-o-swiss humidifiers you can find models that are new and used. Currently some of the popular models are Air o Swiss 7135 the ultrasonic humidifiers, and Air o Swiss 7142 Digital Ultrasonic Humidifiers. These two are often priced below the $300. The model Air o Swiss 7135 is priced below $100 and the more expensive one is the AOS 2055 Digital Ultrasonic Humidifier.
The Ultrasonic Humidifiers often use the high-frequency vibrations to turn the water into a micro-fine mist which is blown into the room, where it immediately evaporates.

