The sensor is to generate a pulse for the tripmaster were there is no workable electronic pulse from the car or where you want to take a pulse from another (non-driven) wheel. The pulse sensor can be installed to detect metal that passes by the head of the sensor.
This low-cost sensor is good to detect reliable 1 pulse in a wheel circumference (in 1 rotation of your wheel).
Thread of M12 x ??mm
NPN Transistor setup
12 Volt power supply (can be directly connected to the tripmaster)