These kits come complete with Ultra 40 8.65mm spiral core wire, terminals, and boots to fit most popular coil and distributor cap combinations. Moroso Ultra 40 Coil Wire incorporates a spiral wound nickel/copper alloy conductor wrapped at the optimum ratio to produce the highest level of spark energy while producing the lowest level of electromagnetic and radio frequency interference. The Kevlar core is four times stronger than other aramid fibers cores, allowing an increase in the tensile strength of the wire while reducing the center diameter and at the same time increasing the surrounding insulation resulting in greater dielectric strength.