10.2mm High Output Racing Spark Plug Wires Triple wound center core for high current discharge improving throttle response. Double silicone insulated to withstand high voltage and power. 10.2mm to withstand high energy ignition coil packs or MSD boxes. Heavy duty boots to withstand high current and resist arcing. Compatible with internal or external coil packs. Heavily insulated so will not make radio noise. Smog legal. Brand New and ready to ship.