CDI Electronics' High Performance Spark Plug Wire sets offer more spark energy, better EMI suppression, and higher dielectric strength when tested against seven leading brands; CDI Electronics beat them all. They offer an optimum capacitance, inductance, and resistance for maximum energy transmission. Their ideal electrical properties provide the best EMI suppression for peak radio electronic ignition performance. They also provide the best insulation performance by providing a silicone jacket over dense EPDM (Ethylene Propylene Diene Monomer).