Cobb Tuning Ford 13-18 Focus ST Cat-Back Exhaust System - 591100EMISSIONS This part is not an emissions related part and therefore can be used on Emission Controlled Vehicles. DESCRIPTION Part of the COBB Stage 3 Package, our 3" Stainless Steel Dual Tip Cat Back for the Ford Focus ST is a direct replacement cat back exhaust that boasts full 304 stainless steel construction, custom inline mufflers, and dual 4" double wall tips, resulting in a unique exhaust note. Perfectly tuned out of the box with the Accessport