The OTR Type AD-IS Style Air Dryer, made with Expertise Built In, completely filters out water, vapor, oil vapor, and other toxins before they get to the air tanks and valves. This heavy duty air dryer thoroughly blocks freeze-up during cold and harsh weather environments. Heavy duty trucks rely on compressed air to actuate braking systems and control the brake operation; this OTR heavy duty air dryer ensures your braking system is in peak condition. FleetPride is your First Click in Heavy Duty.