Original Quality Car Spark Plug Tester Ignition Coil Tester Spark Ignition System Tester Sparking Indicator Diagnostic Tool Quickly diagnose problems with all ignition systems Connect the tool between the spark plug and the plug wire Normal sparks of fire gauges as "purple blue and 2cm straight line," if the ignition coil is bad when the color is red or curve Use this ignition spark tester to check the condition of the ignition system at each cylinder without going to expensive mechanics. The spark tester connects between the spark plug and spark plug wire in seconds to troubleshoot dirty spark plug connections, defective points and bad cables or connections. Connects in seconds. Troubleshoot spark plug connections quickly Easy to use Connects in seconds