ALLOSUN GK500 All-Sun Automotive Spark Tester This tool is to test spark plugs,coils,and distributors on breaker point and electronic ignition systems With the engine running, place the grooved end of the tool over the spark plug wire, the blub will flash to indicate spark Modern and fashionable design of its appearance makes it adorable Mini tester is so easy to carry and test Pocket clip is easier to carry