Equip your semi truck to be ready for the journey ahead with seamless exhaust connections, with the OTR 5" to 4" Aluminized Exhaust Reducer with Expertise Built In. Due to its sophisticated design, this replacement device is able to reduce the diameter of an exhaust pipe so that it can tightly seal with smaller-sized components. Crafted with an aluminized pipe for added corrosion resistance. FleetPride is your First Click in Heavy Duty.