Details and Specifications: Our Performance Exhaust products are made from 16ga mandrel bent steel. Offering both Aluminized and T409 Stainless Steel exhaust systems, we have one of the most diverse products on the market. We have direct fit exhaust kits for your Cummins, Duramax or Powerstroke! With all pre-bent and pre-welded hangers, you never have to guess where a pipe goes – Everything just fits right into place. Exhaust kit details: Pipe Diameter: 4″ Material: 409 Stainless Steel Please note that cab & chassis trucks often have different requirements than standard pickup trucks. If you have a cab & chassis truck, there may be a more specific kit available for your application.