RELIABILITY AND DURABILITY - ARMOR PLUS Series exhaust systems are crafted from corrosion-resistant T409 Stainless Steel - a value-oriented material designed to protect from penetrating rust and will stand up to almostanything you can throw at it. T409 Stainless Steel tubing is easy to clean. If you don’t find yourself faced with lots of precipitation and salt, this is all you’re ever going to need. All of the tubing is mandrel bent for maximum exhaust flow. Mandrel bending ensures no rippling in the bends. The end result is that it gives you m