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. Includes heatshielding. 5/8 inch thick flanges won't warp or flex. One look at Banks TorqueTubes tells you how radically different they are from the stock exhaust manifolds. Constructed of heavy-wall, 400-series stainless steel, TorqueTubes have 5/8 inch-thick flanges that are welded on both sides and then machined perfectly flat (no gaskets needed). They never crack, leak or fail. TorqueTubes tuned-length tubes produce a huge reserve of low-end torque that proves its worth on every steep grade and short onramp. Now your Workhorse climbs faster and stronger, without the transmission struggling between gears. The muscle to stay in higher gears longer not only stops annoying shift happy performance, it lessens the load on your engine and transmission. Here's power to reach freeway speed sooner for safe merging and passing. 5-Year Limited Warranty. Torque Tube Exhaust Header System for use with 2004-2010 GM 8.1L W-Series Motorhome, No EGR Key Features: Virtually indestructible 100 percent 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 Pulls exhaust and slashes backpressure Includes heatshielding 5/8 inch thick flanges won't warp or flex