Autolite 103 Spark Plug Copper Core (4 Pack) Brand New Box of 4 Autolite Spark Plugs Genuine Autolite Part # 103 Copper-glass seal bonded insulator, terminal post, and center electrode provide a tight seal that is 100 percent leak-proof Multi-rib insulator reduces danger of "flash-over" to prevent misfires Full copper core electrode improves heat transfer and optimizes plug life