1Versatile: This probe pen is perfect for checking circuits, fuses, switches and wiring on cars, trailers, boats, motorbikes and other low voltage systems. 2Bi Directional Test Mode: The digital display allows you to see the test results more clearly, giving you a better experience. To upgrade the bi directional voltage circuit tester, connect the clamp to negative or positive ground and the light emitting diode on the circuit board is used for polarity indication, with a red light indicating positive polarity and a green light indicating negative polarity. 3Professional Test Tool: The car truck circuit test pen has a 3V to 70V Dc test range and is ideal for checking the circuitry of a wide range of vehicles, quickly checking the wiring and circuitry of car headlights, taillights, turn signal circuits, faulty sockets. 4High Class Material: Carbon steel probe for piercing wires, is also suitable for use in difficult to reach confined areas. The heavy duty test light body is made from high grade Abs which is shatterproof and more durable than ordinary test lights. 5Lightweight and Portable: With its portable size and easy storage, this automotive circuit tester has a lightweight design that is very easy to carry. You can easily store this tool in your car.