D-Series breathers feature seven different models designed to satisfy the requirements of most stationary applications involving hydraulic reservoirs, lubricant and fuel storage tanks, transformers, pumps and gearboxes. D-Series models provide application flexibility by using 100% silica gel for moisture adsorption or 100% activated carbon for fume or odor control, or a mixture of both when necessary. All D-Series models feature 2 micron solid particle filtration and are available with airflow ratings of 35 cfm to 250 cfm. The D-Series is constructed of industrial grade raw materials and feature high impact resistant ABS top and bottom caps. The clear acrylic window makes it easy to inspect the condition of the color changing silica gel from a distance. The silica gel turns color from gold to green to visually indicate the adsorption of moisture and confirm the breather is doing its job! All Air Sentry raw materials have been tested to ensure chemical compatibility with a wide range of industrial lubricants, fuels and fluids.