RWA1582-40 is manufactured by Cometic and uses their MLS process. Multi Layer System. Cometic MLS head gaskets are constructed from multiple layers of stainless steel for strength and contain load-controlled embossments that conform load distribution across the sealing area. This creates an exceptional seal by requiring less clamp load--resulting in less bore distortion. The stainless steel outer layers utilizing FKM (Viton®) rubber coating, a high-temperature and chemical-resistant polymer. A topcoat of PTFE aids in resistance to fret and increased cold sealing. MLS head gaskets are available for most aftermarket cylinder heads; as with all of Cometic's MLS head gaskets, no sealants or re-torque is required. Bore (in): 3.642 in. Bore (mm): 92.500mm Gasket Material: Multi-layer stainless steel Compressed Thickness (in): 0.040 in. Compressed Volume (cc): 6.828cc Lock Wire: No