COBB Ford Cat-Back Exhaust Focus RS Mk3 2016-2018COBB 3" Stainless Steel Dual Tip Cat Back for the Ford Focus RS is a direct replacement cat back exhaust that boasts full 304 stainless steel construction, custom inline straight through resonator plus muffler, and dual polished 4. 5" double wall slash cut tips. Our exhaust also features the same OEM exhaust valve found in the stock cat back, so there is no need to remove and transfer the original unit. The exhaust valve is a direct plug and play