Center or shim layer is uncoated stainless steel, which can be varied to accommodate multiple thickness requirements Outer layers are embossed and coated on both sides with Viton to meet the demands of a variety of harsh sealing environments, load conditions, and surface finishes MLS (Multi-Layer Steel) head gaskets promote an even torque load across the gasket sealing surface utilizing LCE (Load Control Embossments), providing less bore distortion and better piston ring seal for more power Made in the U.S.A.. GASKET HEAD 4.000"X.030"