Flowmaster's American Thunder cat-back exhaust system for the 1998-2003 Ford F-150 pickup truck is perfect for the person looking for an aggressive sound level with all of the performance benefits that you would expect from Flowmaster. This DOR or DOS (Dual Out Rear, Dual Out Side) bolt on 409S stainless steel system for the 4.6L and 5.4L V8 engines features dual 2.50 inch tailpipes and 3.50 inch polished stainless steel tips. This system is designed to fit all wheelbases and uses Flowmaster's Super 40 Series muffler. The exhaust system is manufactured in the USA and is covered by Flowmaster's Lifetime Limited Warranty. Designed for an easy fit, this system includes all necessary parts and hardware for installation.