Auto Meter 2891 Performance Tachometer Traditional incandescent lighting illuminates around the perimeter of the dial 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 Auto Meters race proven air-core electric tachometers provide quick and accurate readings with a needle so responsive it can go from 0 - full scale in 333 milliseconds Compatible with 2 - 4 pulse ignition signals (4-8 cylinder engines) with points, electronic, and most 12V high-performance racing ignitions.