Buddy Club Racing Spec Head Gaskets are metal reinforced and are designed to withstand the extreme temperature and cylinder pressure of an ultra high output engine. Buddy Club selected stainless for the material of the gasket, which makes it possible to cool down the cylinder effectively by transferring heat to the cylinder head equally with the high thermal conductivity of stainless. These are the best "thin" headgaskets around! They are manufactured by the same OEM that produces them for Honda. So you are getting the same material and quality, therefore, no worries. These are a two layer configuration, measuring out to 0.5mm or 0.020in(thousanths). A stock headgakset is 0.8mm or 0.030in. These are perfect if you want that tiny bump in compression, such as in a factory un-milled ITR, GSR or B16A engine.