These super high quality gaskets were invented by German engineers for the 1700 and 1800cc Vanagon engines. We routinely use them on our high end engine builds where reliability is of the utmost importance. One side of the gasket is solid zinc plated steel. We usually put this side against the head as a barrier to hot exhaust gasses. The steel is formed around the gasket material, making the gasket virtually blow-out proof. We have seen these gaskets in service for several years, and then re-used again due to their perfect condition! The inner diameter is 1.4 inches, making them work on stock and mildly ported heads. Set of four. Made in Germany.