Thermo Tec Thermo-Flex x2 Plug Wire Heat Shield Pack Of 2 Attractive durable finish this heat shield is manufactured with a combination of materials to provide thermal insulation and radiant heat protection. thermo-flex plug wire heat shields can withstand extreme temperatures of 1050 degrees f. the heat shield offers protection for spark plug wires and boots from conductive and radiant heat with the durability of stainless steel. each heat shield comes with a plug-wire centering grommet to provide protection to the wire as it exits the heat shield.