Keeping track of the vacuum and boost on your forced induction application is critical for extracting the most power safely while keeping your engine in the powerband. AutoMeter?s Digital Stepper Motor Boost/Vacuum Gauges provide the most accurate eadings available, unparalleled response time and smooth needle movement. Taking advantage of AutoMeter?s advanced circuitry, these gauges automatically calibrate on every startup to compensate for altitude, barometric pressure and other atmospheric conditions. Includes an advanced MAP sensor and wiring harness for ease of installation. Designed for gasoline engines, a boost only version is also available for diesel or extreme boost applications. Modern LED through-the-dial lighting provides clear visibility during nighttime use GM BLACK