Traditional incandescent lighting illuminates around the perimeter of the dial. Works with most Pre-1989 (Pre-1987 Mustang) Ford and most Chrysler. 12 and 16 volt compatible well-suited with nearly every street car or race car electrical system. Gauge kit includes bulb and socket assembly red and green bulb covers mounting hardware and detailed instructions for installation. Autometers Race Proven Air-Core Electric Instruments Provide Quick And Accurate Readings