Traditional incandescent lighting illuminates around the perimeter of the dial. Autometers Race Proven Mechanical Instruments Provide Trusted Accuracy While Being Simple To Install. No electrical system required for gauge operation - compatible with every street or race vehicle. Gauge kit includes 1/8" nylon line T-Fitting vacuum fitting compression fittings bulb and socket assembly red and green bulb covers mounting hardware and detailed instructions for installation. Mechanical movements provide accuracy and durability even in the harshest environments