If you are having an exhaust built for your your car the BWR Header Flange is an essential peice to get your project done. We designed these flanges to work with both your factory header as well as your aftermarket race header. The flange allows you to utilize the "donut" gasket to ensure a leak free exhaust system.They are made from high quality 304 stainless steel that ensure the highest quality and an extremely long lasting product.