MrC10 LS Engine Ignition Plug Wire Sets are proudly Made in the USA with a 100% silicone 8.0mm outer jacket for the highest heat resistance properties and can withstand extreme engine and exhaust temperatures. Each wire is built using two extruded layers of silicone that are bonded together with fiberglass braided mesh to virtually eliminate terminal pull-off. We use a very low 250 Ohm/ft dual wound core with a 7-layer carbon latex coating to absorb RFI. Stainless steel wire is also wound around the base core for faster current delivery and a more complete burn cycle. To complete the package, our wires include solid brass and stainless terminals to maximize performance, and our high silicone content boots protect you from high temperatures. Our wire sets also include high temp aluminum heat shields that protect up to 1200 degrees. Designed Truck Tough.