The Metal Mulisha Exhaust System line by Gibson Performance is easily the most unique performance exhaust system line we've seen to date. If the name doesn't already imply it, these systems are mean! Gibson Metal Mulisha Performance Exhaust Systems feature 4" diameter stainless steel piping that is mandrel bent for optimal flow. At the end of the system is a ceramic coated black exhaust tip with the famous skull logo featured on the side. The edge of the Metal Mulisha Exhaust tip is rolled for an improved look. The Gibson Metal Mulisha Performance Exhaust packs a mean sound. You'll gain horsepower and most users report a small increase in fuel economy / efficiency. Gibson Metal Mulisha Exhausts are Made in the USA and backed by a limited lifetime warranty. The part number for this item is 60-0019 and it fits 2011-2014 Ford F250 F350 Super Duty (6.7 Diesel Models)(6 1/2' Short Bed Only). This is a 4" Diameter system with an 8" tip that exits on the passenger side behind the rear tire.