27% nickel clad copper was developed for use in applications where high temperatures, oxidizing, or corrosive atmospheres exist. It has electrical conductivity approximately 70% that of copper and the corrosion resistance of pure nickel. Nickel clad copper is produced to ASTM B-355 in sizes 20 AWG and finer. Enamel insulations are also an option. See the magnet wire insulation guide for film selections.