Package contains: (as shown in the picture) 1 x RPM signal adapter Model: GR01 1. Cable definition red: power supply 12V DC black: power supply GND black/brown (1.6m ): Input signal wire Blue: Output signal (fixed 4 pulse/rev speed ratio) Brown: Switch control wire 2. Configuration steps: 1) Connect the switch wire to enter the setting mode 2) Find the ignition coil of the gasoline engine, usually it is close to the spark plug , can be easily found in the engine/car/vehicle owner's guide. Wrap the input signal wire around the ignition coil cable 5~8 times, then tighten it as follows: 3) Turn on the sensor power, the LED will remain green 4) Disconnect the switch wire, the LED will still remain green and count the pulses detected from the engine 5 ) Connect the switch brown cable and disconnect again, the LED will flash 6) The sensor outputs a pulse signal with a fixed RPM ratio of 4 pulses/revolution, which means it will output 66.6Hz at 1000RPM. For example, if the input frequency is 100Hz@1000RPM, the sensor will convert the signal and then output 66.6Hz@1000RPM7) How to configure the tachometer? Please set your tach/tachometer RPM ratio to 4 pulses/rev, then the meter will work normally. Model: DR01 1. Cable definition Red: Power supply 12V DC Black: Power supply GND Yellow: Output signal (fixed 4 pulse/revolution speed ratio) White: Switch control line 2. Configuration steps: 1) Connect the switch line Enter the setting mode 2) Find the original alternator of the vehicle, then install DR01 on top of the alternator like below, and install it tightly: 3) Turn on the sensor power, the LED will remain green 4) Disconnect the switch wire, the LED will still Stay green and count the pulses detected from the engine 5) Connect the switch brown cable and disconnect again, the LED will flash 6) The sensor outputs a pulse signal with a fixed RPM ratio of 4 pulses/revolution, which means it will output 66.6 at 1000RPM Hz. For example, if the input frequency is 100Hz @1000RPM, the sensor will convert the signal and then output 66.6Hz @1000RPM7) How to configure the tachometer? Please set your tach/tachometer RPM ratio to 4 pulses/rev, then the meter will work normally. Welcome