Our gasket is made with a Multi Layer Steel construction, similar to the OEM gasket. We feature a durable stainless fire ring design to promote sealing against the flange surface. Keeping your exhaust gases inside the manifold, right were they need to be. Specs: 1.25 mm Thickness Layers: 4 Layers OEM Part Number: 14038AA000 Specs: 1.25 mm Thickness Layers: 5 LayersTurboXS EJ Exhaust Manifold to Head Gasket (Pair) Subaru