BC gaskets are made in Japan and deliver the ultimate sealing capability even at extreme boost pressures. Individual die cut layers of stainless steel with superior consistency compared to other leading gaskets. These inferior brands are constructed with too high profile of beads which is prone to fatigue, losing the spring effect in a relatively short period of time and consistency of sealing pressure, resulting in leakage. BC gaskets are pre-coated stainless steel with a 0.2 micron consistent layer of Nitrile rubber that completely fills the cylinder head surface. Even a newly resurfaced cylinder head and/or block has a surface finish or roughness between 10 to 15 microns and this Nitrile rubber completely seals the surfaces at operating engine temperatures, unlike the FKM type which is not suitable for filling the surface roughness because the material has too high of heat resistance. Basically the FKM does not melt to fill into the surface roughness providing the proper seal.