Virtually indestructible 100 Stainless Steel. Mandrel - formed tubes tune exhaust flow for maximum torque. Maximize exhaust extraction. Flanges welded on both sides, then milled flat. Seamless high - velocity collector. Exclusive tuned - length parallel 5 - tube design. Patented PowerPickle pulse converter. 58 inch thick flanges won't warp or flex. Includes Y - pipe heat shielding. Virtually indestructible 100 percent stainless TorqueTubes maximize exhaust extraction, unleashing gobs of torque. Exclusive tuned - length, parallel 5 - tube exhaust manifolds designed specifically for motorhomes. 5 - Year Limited stainless steel construction never cracks or blows. Mandrel - formed tubes tune exhaust flow for maximum torque. Patented PowerPickle pulse converter maximizes exhaust extraction. No sealant or gaskets required. 58 inch thick flanges never warp. Flanges welded both sides, then milled flat. Includes stainless Y - pipe assembly with seamless Y - collector. Includes necessary heat shielding. 5 - Year Limited Warranty. US Patent 8,468,812 B1