This Mid - Pipe is used to connect the BORLA Axle - Back PN 11961 to the factory catalytic converter creating a Cat - Back system with 2 diameter pipes. Built from premium T - 304 austenitic stainless steel, superior to T - 400 series knockoffs (such as 409), to give you the absolute best in performance and durability. Ultra - smooth mandrel bends ensure maximum flow power, and precision computer numerical control (CNC) manufacturing ensures an accurate fit. Best of all, BORLA stands behind every mid pipe with a Million - Mile Warranty. Just what youd expect from the worlds most experienced (and most winning) exhaust brand.