Faria Beede Instruments 4" Tachometer w/Hourmeter 4000 RPM Diesel Mech Takeoff & Var Ratio Alt Euro

Faria Beede Instruments 4" Tachometer w/Hourmeter 4000 RPM Diesel Mech Takeoff & Var Ratio Alt Euro. Electronic tachometers work by counting pulses generated by the ignition system alternator tach signal generator or magnetic pickup sender. The tachometer 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. Th