Finally, an exhaust system as durable and strong as the trucks it's designed to fit. Flowmaster® proudly introduces the American Thunder® cat-back exhaust system for 2001-2006 Chevy and GMC 2500HD/3500HD extended-cab and crew-cab trucks equipped with the 6.0 and 8.1L engines. Featuring dual 3.00 in. inlets and a single 3.5 in. mandrel-bent tailpipe thats finished off with a large 4.00 in. polished T304 stainless steel tip. This stainless steel system features a 50 Series Big Block® muffler gives your truck a deep moderately aggressive tone inside and out. Detailed step-by-step instructions and all necessary hardware are included to allow an easy, at-home installation. The system is covered by our Lifetime Limited Warranty.