In addition to the high performance filtration packages that are an inherent part of each Graham-White Air Dryer, we also make available an assortment of stand-alone, heavy-duty filters. These unique, high efficiency, stand-alone filters fall into two groups. The first group is a series of Centrifugal / Coalescing filters with automatic drains. The second group is comprised of high efficiency Particulate Filters. It is important to remember that a Centrifugal /Coalescing filter is not an air dryer that reduces the dew point or the relative humidity of the compressed air. Although the Centrifugal filters will remove some of the free water and the Coalescing filters will remove free water and oil aerosols, they do not remove the water vapor that will eventually condensate as the compressed air temperature cools.