Solid Copper Gaskets have been around since the early days and are still used on todays high performance Top Fuel Engines and other applications. The Head Gasket is still the most stressed static seal in the engine, and to have one fail is not desirable. An Idea that was developed in the early days of internal combustion is still here to assist in having a really powerful engine. Yes it is a flat Plain Copper Gasket. They were in a Model T and now are used in so many engines today.