Blue These low resistance, high performance wire sets feature two current paths. One path is spiral wound stainless steel alloy and the other is a carbon impregnated fiberglass center core. Other features include low 500 ohm per foot resistance. Silicone jackets used to resist high temperatures, moisture, oil and chemicals. EPDM rubber inner insulation for superior heat resistance and prevention of arching and voltage leaks. Fiberglass reinforcing braid for added strength and flexibility. Available in red, blue and black, these spark plug wires come with a lifetime warranty and are made in the U.S.A.