Auto Meter 233904 Autogage Monster Shift-Lite Tachometer Traditional incandescent lighting illuminates the front of the dial 12 and 16 volt compatible, well-suited with nearly every street car or race car electrical system 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. Optimize use of your engine's power band and improve vehicle run performance and driver gear changes with a rapid response, high visibility user-programmable shift light.