Faria Beede Instruments Euro Black 4" Tachometer w/Systemcheck Indicator - 7000 RPM Gas - Johnson / Evinrude Outboard. The tach is hooked up to +12VDC Ground and one of the signal sources listed above. By selecting the right tach and setting the switch on the back to the correct position you let the tachometer know how many pulses are sent per each engine revolution. These tachometers have a warning light system built into the dial that show off warning indicators when a fault is detected from the engine. SystemCheck warnings No Oil Engine Overheat Check Engine Low Oil Specifications for Faria Beede Instruments Euro Black 4" Tachometer w/Systemcheck Indicator: Manufacturer: Faria Beede Instruments Color: Black Features of Faria Beede Instruments Euro Black 4" Tachometer w/Systemcheck Indicator Wide range of scales Available for gas or diesel engines Multiple signal sources Rugged Reliable construction 4" - Hole size: 3.375" (85mm) Package Contents: Faria Beede Instruments Euro Black 4" Tachometer w/Systemcheck Indicator Faria Beede Instruments 32850: Euro Black 4" Tachometer w/Systemcheck Indicator - 7000 RPM Gas - Johnson / Evinrude Outboard