The Banks 48634 Single Monster 4 Inch CAT-Back Exhaust System is the perfect solution for your 2002-2005 Duramax. This muffler reduces in-cab drone, lowers exhaust gas temperatures, and is made of 4” mandrel bent stainless steel construction. It also features a side exit chrome or black rolled-edge exhaust tip. This system comes with a 5 year limited warranty.