4" stainless constant-diameter pipes and straight-thru muffler nearly doubles flow. Lower exhaust temps; virtually no backpressure; rich, throaty sound. F-250/350/450/550 PICKUP & EXCURSION: Monster exhaust system flows up to 91.5% better than stock and virtually eliminates backpressure. The streamlined 4" intermediate pipe(s) and tailpipe are formed of stainless, heavy-wall tubing with constant-diameter bends to maximize flow and lower exhaust gas temps. Banks replaces the factory's restrictive muffler with a polished-stainless steel Monster muffler, featuring a straight-through 4"-diameter flow-path with a Banks-designed expansion chamber which dissipates the annoying mid-range exhaust drone that's so prominent in competitors' straight-through mufflers. The muffler utilizes spun ceramic, very-high-temperature packing, more than doubles the stock flow and delivers an authoritative°but never intrusive°exhaust sound. Includes a 3-1/2" turbine outlet pipe (T.O.P.).* A huge 5" stainless steel tailpipe tip in polished chrome or black sports a rolled edge. Double-walled design with 1/2" air gap keeps heat from tarnishing the exterior mirror finish. Adjustable clamp for positioning on tailpipe. *For 2006 models with manual transmission, Banks T.O.P. not required.