Brown Primary Wire, 18 Ga (500 ft.) Single conductor copper stranded polyvinyl chloride insulated primary wire is standard for original equipment and replacement automotive applications. Smooth surface makes it ideal for pulling through loom or conduit. Rated for 12 volts insulation operates optimally between the temperatures of&lt;br&gt;-29F to 194F and -34C to 90C. Meets or exceeds S.A.E. specification J1128 Ford M1L56A and Chrysler MS 3450. Highly resistant to grease oil and acids.