Get your semi truck ready for the long haul with seamless exhaust connections, with the OTR 5" to 4" Aluminized Exhaust Reducer with Expertise Built In. With a sophisticated design, this replacement piece works to reduce the diameter of an exhaust pipe so that it can tightly seal with smaller-sized components. Built with an aluminized pipe for boosted corrosion resistance. FleetPride is your First Click in Heavy Duty.