Product Details: The OTR Type AD-9® Style Air Dryer ensures Expertise Built In™, thoroughly filtering out water, vapor, oil vapor, and other contaminants before they get to the air compressor tank and valves. This heavy duty air dryer efficiently blocks freeze-up during cold and harsh weather conditions. Heavy duty trucks rely on the compression of 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®.