Vibrant Performance's BMW E36 Exhaust Manifold Flange and E46 Exhaust Manifold Flange will save you the time and high cost of getting header flanges cut when you need to fabricate a custom header or turbo manifold. This flange is cut from 1/2'' (12.7mm) thick Mild Steel. The port sizing on these E36 and E46 exhaust header flanges is optimized for use with Schedule 10 or Schedule 40 pipe.