Mr. Gasket Embossed Steel Shim Cylinder Head Gaskets are for high performance street machines, drag racing and oval track racing. This is a very unique design that has a solid metal on metal fold at the combustion seal. This fold makes for a very stout seal that is almost the equivalent of a higher-end MLS (multi-layer steel) gasket with a gas stopper layer, but at a much lower cost. This gasket also has embossments around the coolant and oil passages and has a thick aluminum flake coating. All of these features result in a steel shim head gasket that handles extreme cylinder pressures very well. It's probably the best steel shim head gasket you could ask for. Sold individually.