The Mr. Gasket Square Port, Large Race Ultra-Seal Exhaust Gasket is manufactured from high temperature steel core / graphite faced exhaust material. Exhaust manifold gasket seals the connection between the manifold and cylinder head. This prevents exhaust leakage out of the connection and also ensures that all exhaust gas will flow through the catalytic converter for treatment. Flange and ring gaskets seal other connection points in the exhaust system, such as between the exhaust pipe and exhaust manifold. This ultra-seal exhaust manifold gasket can be trimmed if necessary for modified ports. It is packaged 2 per set.