A. How does it work? It can sense the magnetic signal changes when the vehicle's original alternator is running, and then output a 9V voltage for various tachometers/revolution per minute meters. B. It is relatively easy to install. There is no need to break the wires, and no CANBUS/OBD interface is required. C. Rotational speed output: 4 pulses per revolution. D. It has achieved an IP67 waterproof rating. E. It is relatively compact and adopts a plug-and-play design. F. Power supply: 9 - 36V DC. G. Model: Suitable for gasoline engines. H. Material: ABS plastic. I. Color: Black. J. Package contents: 1 speed sensor. Only the above package contents are included, and other items are not typically included. Note: Light reflection and different displays may cause the color of the item to vary slightly from the actual object. The allowable measurement error is around +/- 1 - 3 cm.