The HP shim technology increases clampload around the combustion chamber, thereby increasing the sealability of the head gasket around the open deck block. COMETIC MLX (Multi-Layer Stopper) gaskets utilize an integrated stopper layer for combustion chamber sealing and improved clamp load around the cylinder without increasing bore distortion. MLX technology can be found in some head gaskets and are made from the same materials as our MLS Head Gaskets. No sealants or re-torque required