Air Sentry D-Series breathers feature numerous models in a variety of sizes, designed to satisfy the requirements of most stationary fluid management applications. The breathers provide application flexibility by using 100% silica gel for moisture adsorption or 100% activated carbon for fume and odor control, or both when necessary. All D-Series models feature 2-micron solid particle filtration and are available with airflow ratings of 20 cfm. The D-Series is constructed of industrial grade raw materials, tested to ensure a wide range of chemical compatibilities, and features high impact resistant ABS top and bottom caps. The clear acrylic tube makes it easy to inspect the condition of the color-changing silica gel from a distance. The silica gel turns from gold to dark green to visually indicate the adsorption of moisture and confirm the breather is getting the job done!