Motorcraft SP-478 Spark Plug Same part that was installed when the vehicle rolled-off the assembly line Designed to deliver quick starts, enhanced fuel economy and smooth acceleration with 100,000 mile service interval Copper Core electrode, Nickel Chromium Alloy side electrode for excellent heat dissipation & durability Copper-glass seal bonds insulator, terminal post center electrode together; assures full required voltage at spark gap; gas-tight seal