Auto Meter 6809 Pro-Comp Memory 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 0.5 - 6 pulse ignition signals (1-12 cylinder engines) with points, electronic, and most 12V high-performance racing ignitions. Triage engine health and setup changes using Peak RPM Memory recall with one touch review. Commonly referred to as the 'tattle tale' in the racing world, this function allows racers to gain quick insights between rounds about wheel spin, gearing and gear changes.