PMC (Precious Metal Customs) extends its line of exhausts with this model called Shank. Like all other exhausts of their line they are made of Stainless Steel and polished to a high shine. Stainless naturally goldens after being run but can always be returned to a high chrome-like finish with a little polishing. One great feature, taken directly from Nascar Technology is the welded-on flanges. The flanges come with a high temp O-ring seal so there are no more snap rings or clamps to deal with. Thanks to these welded flanges, there is no need for any external mounting and it bolts rigid to the engine heads. Precious Metal Customs.