Regenerative desiccant drying systems provide the greatest level of drying capability amongst widely available drying technologies.  The ID and IDW series are heatless units that produce atmospheric dew points of -22°F (-30°C) and below, and ISO 8573-1 moisture classes of class 3 and better.  Heatless designs alternate between 2 desiccant columns and use a small portion of the dry air from the column in service to regenerate the other column, thus assuring continuous capability of providing dry air.