This BBK Performance short mid pipe is specifically designed to be used with BBK CNC series long tube exhaust headers for the 2016-2020 Mustang GT350 part # 1856 / 18560 to complete installation to your factory resonator box or resonator delete X pipe.These mid pipes are made from CNC mandrel bent 3.0 inch Tubing and feature high flow catalytic converters and a merged step down to allow installation to the factory exhaust system. Each BBK mid X pipe offers performance, quality and value that guarantees years of top performance for your Ford Mustang.Required for installation of BBK Long Tubes 1856, 18560 etc