6 Gauge set included: 160MPH Speedometer, 8000RPM Tachometer, Fuel, Water temp, Volt meter, Oil pressure Speedometer and tachometer: Panel color:Black Backlight Color: Red Fixing dimension: 85mm(3-3/8″) Working voltage:932VDC Suitable for car truck boats off-roadvehicles boats This tacho must be hooked up to the “W terminal on vehicle alternator. Many diesel engines and most inboard gas boat engine alternator have this connection. It can also be working with tachometer sender Minor gauges: Install Diameter: 52mm/(2-1/16) Oil Pressure: 10184ohms, 0-145 PSI(0-10Bar) Fuel Level: 240-33ohms, E – F Water Temperature: 287.422.4 ohms, 100-250F(40-120C) Volt: 8-16V.