Features: 1.Grooved end makes the contact area between the wire and the instrument large, ensure accurate test. 2.Quality light bulb, high brightness, easy to observe, convenient to use. 3.With portable pen clip, easy to carry and store, bring much convenience for you. 4.Conform to strict quality control standards, dependable to use. 5.Stable characteristics, professional performance, high reliability. Specification: ?Condition: 100% Brand New_x000D_ Item Type: Ignition Test Pen_x000D_ Material: Alloy_x000D_ Color: As picture shown_x000D_ Length: Approx. 125mm/4.9in_x000D_ Diameter: Approx. 10mm/0.4in_x000D_ How to Use:_x000D_ When the engine is started, place the grooved end of the instrument on the spark plug wire. If the bulb flashes, the spark plug wire is transmitting the spark signal._x000D_ 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. Note: Recommended for professional use.