Armor Pro™ 304 SS Street Profile Axle-Back Exhaust System with Split Rear Exit (S44503CF) by MBRP®. Exhaust System Type: Axle-Back. Exhaust Tubing Material: 304 SS. Main Tubing Diameter: 2.5". Exhaust System Sound: Moderate. The MBRP Armor Pro™ is designed and built for the most serious enthusiast who will settle for nothing less than top of the line. The Armor Pro™ exhaust systems are crafted out of T304 Stainless Steel - the most durable material grade that money can buy. The T304 Stainless Steel tubing is easy to clean and maintain. It’s the obvious choice for you if you operate your vehicle in extreme conditions. All of the tubing is mandrel bent for maximum exhaust flow. Mandrel bending ensures no rippling in the bends.