2011-2014 Mustang Roush V6 3.7 Axle Back Dual Exhaust Kit Black Tips Fits 2011-2014 Mustang 3.7L V6, Coupe and Convertible Unique open-chambered design provides increased horsepower and torque by increasing airflow and reducing back pressure 409 stainless steel pipes and muffler 304 stainless steel exhaust tips that have been powder coated black Does not negatively affect emissions Same as Roush's regular 421145 V6 exhaust but with black tips