Multiple Layer Steel (MLS) type of gaskets have increased strength against vibration and corrosion, and have of multi-layers of steel with an additional sealing layer. This additional layer is an HR-180 Rubber coating for superior sealing. MLS head gaskets are the proven choice for high-performance engines. Stopper type gaskets come in several styles, all with extra material strategically sandwiched between the layers to improve sealing against the increased power and vibrations found in high-performance engines. These types of gaskets are also ideal for installation when there is minimal surface around the combustion chamber or cylinder walls, i.e. due to boring for additional cylinder size.