TEGIWA Triangle Exhaust Flange. Constructed from 8mm stainless steel here in the UK, these triangular exhaust flanges are of OEM quality. They have a true size bores, making them perfect for numerous exhaust systems. We have two sizes, 2" and 2.5" available in triangle shape. We also sell oval shaped 2-bolt flanges and suitable high-quality gaskets to seal any joints.