The MagnaFlow XL 4 X 9in. Oval Multi-Chamber Performance Exhaust Muffler 13266 features a straight-through weight-optimized reversible design with a perforated stainless steel core featuring baffles and tuning gates enabling it to deliver the powerful signature sound and dyno-proven performance that's made MagnaFlow a household name. Muffler 13266's oval-shaped 4x9x18in. body and universal 2.5/2.5in. diameter inlet/outlet layout enables flexible installation options to match the spacing requirements of your vehicle. Professional installation is highly recommended. 13266 is produced using advanced CNC precision robotic manufacturing techniques and features durable corrosion resistant stainless-steel construction all backed by MagnaFlow's limited lifetime warranty.