1/4” outlet pipe. First Stage - 5 micron particulate filter removes water in a liquid form as well as dirt, debris and pipe scale. Second Stage - .01 micron oil removing filter removes oil aerosols and microscopic particles removed. Third Stage - Desiccant dryer adsorbs water vapor from the air, producing a -30° F dew point. Fourth Stage - 3 micron absolute filter filtrates desiccant dust. Fifth Stage - Precision regulator reduces pressure to required level.