Dead-soft solid copper collector gaskets measuring .043 inch thick with a raised .051 inch embossment that conforms to minor surface irregularities for a reliable seal. Engineered for extreme heat environments found in high-performance street, drag racing, oval track, and turbocharged applications. These gaskets provide excellent durability, withstand intense exhaust temperatures, and remove easily during disassembly. Ideal for 2-1/2 inch, 3-bolt round header collectors.