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. 5/8 inch thick flanges won't warp or flex. Includes all necessary hardware.Virtually indestructible 100 percent stainless TorqueTubes maximize exhaust extraction, unleashing gobs of torque. Banks TorqueTubes maximize exhaust extraction and torque. Stainless steel construction never cracks or blows. Mandrel-formed tubes tune exhaust flow for maximum torque. Patented PowerPickle pulse converter maximizes exhaust extraction (see the big PowerPickle). 5/8 inch thick flanges never warp. Flanges welded both sides, then milled flat. Banks streamlined, stainless steel TorqueTubes are the industry's only parallel 5-tube exhaust manifolds for RVs. Unlike competitors who add a separate tube length to a 4-tube formation, Banks integrates five tuned-length tubes into a design that allows rotational firing of the cylinders through the exhaust, minimizing backpressure and maximizing torque. The thick, 5/8 inch flanges never warp or leak. Maximize exhaust extraction and torque. And check out that amazing PowerPickle! 5-Year Limited Warranty. US Patent #8,468,812 B1