Manufactured from three stainless steel layers, resists corrosion, will not burn through or push out and maintains maximum fastener torque retention. Stress formed inner and outer layer embossments act like springs that rebound under exhaust flange clamp load, creating force to seal excessive exhaust pressure produced from cylinder heads Withstands different combinations of cylinder head (aluminum) and exhaust header or manifold (steel) materials, will not deteriorate from scrubbing action caused by different expansion rates in aluminum and steel material.