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.