Professional Red 4 Tachometer - 7,000 RPM with System CheckThe Faria Beede Professional Red features perimeter-lighted Black dial with stylish Red and White graphics, Black aluminum bezel, tear- drop White pointer and flat glass lens.Electronic tachometers work by counting pulses generated by the ignition system, alternator, tachometer signal generator or magnetic pickup sender. The tachometer is hooked up to +12vDC, Ground and one of the signal sources.These tachometers have a warning light system built into the dial that show off warning indicators when a fault is detected from the engine. Available with SystemCheckA(R) or OBD warning systems. 4- Hole Size: 3.375 (85mm)For Engine Types:Johnson/Evinrude Outboard MotorsSpecifications:Flat Glass Anti-fog, Scratch Resistant LensBlack Aluminum BezelLED Illuminating around the Perimeter of the DialTear Drop White PointerFactory P/N TC9934*Sold as an Individual**Gauge Cover not Included