​Condition: Brand New Item Type: Ignition Test Pen Material: Alloy Color: As picture shown Length: Approx. 125mm/4.9in Diameter: Approx. 10mm/0.4in How to Use: When the engine is started, place the grooved end of the instrument on the wire. If the bulb flashes, the wire is transmitting the spark . This product can be used to test spark plugs, coils and distributors in two places, the electronic ignition system and the circuit breaker. The grooved end makes the contact area between the wire and the instrument larger, and the high-brightness bulb makes the measurement results easy to observe.