E3 Straight Boot Universal Racing Wire Set - 40 Ohm Spiral Core, 8.5mm Straight Boot Plug Wire Set for Racing & Street. These DiamondFIRE 8.5mm racing wire sets are designed to maximize the power of E3 Spark Plugs DiamondFIRE Technology. Sporting a Class F40 Spiral Conductor and rated at just 40 Ohms per foot, the 8.5mm silicone outer jacket encases a silicone inner jacket with stainless steel terminals. All racing wires sets are build to suit with all the necessary components. The distributor end comes unassembled, but includes multiple terminals for different applications. Boots are available in straight or 90 degree configurations.