ATD Tools 78881 Filter Element Change Kit for ATD-7888 Desiccant Dryer Stage 1 - 5 micron particulate filter element (EK35-5) Stage 2 - .01 micron oil removing filter element (EK55A) Stage 3 - desiccant dryer dispersion element, intake tube element, O-ring Stage 4 - 3 micron absolute filter element (EK35-3) Filter Element Change Kit for ATD-7888