The FLO 753NB is a 4" downpipe back dual exhaust system by FLO-PRO for the 2011-2019 Ford 6.7L. It replaces your restrictive OE exhaust system from the downpipe back with a 4" mandrel-bent dual exhaust system. Just like all of Flo-Pro's Exhaust kits, it will come with all the required clamps, pre-weld contour bent hangers, and stronger flanges to help you cruise through the installation process. The FLO-753NB does not include a muffler and is intended for the track driven 6.7's! This kit not only sounds great but will improve the torque, mileage, and throttle response on your 6.7L!