Quickly diagnose ignition system problems, lack or no spark condition. Easily test ignition circuit continuity at each cylinder. The tool connects between the spark plug and the plug wire. Great for trouble all internal combustion engines Find dirty spark plugs, defective points, bad cables or connections, etc. name:Spark Plug Tester Condition: New Length: 270 mm (10.8inch) Suitable for: Testing the car ignition system work Usage Method: 1. With engine off, remove spark plug wire. 2. Attach black connector spark plug. 3. Insert metal end of tester into spark plug wire. 4. Try to start the engine. 5. If ignition circuit is complete, bulb flash. Colour: black + white Material: ABS Package Contents: 1 x Spark Plug Tester Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.