Virtually Unlimited Application According to S ' G Tool Aid, their 23970 In-Line Spark Checker Kit for recessed plugs is the 1 ignition spark troubleshooting device for virtually all domestic and import cars, SUVs and trucks. This kit can enable you to test newer vehicles with recessed spark plugs, in addition to conventional and coil-on plug ignition systems. Each kit includes: a coil tester, a coil tester extension, a female-female adapter for testing conventional ignition systems and a battery clip for testing directly to ground. Each component in the kit is identified by a safety orange color for easy visibility. The coil tester is equipped with a flashing bulb to indicate whether there's a problem present, then the flash's frequency and intensity reveals if it's an ignition system problem or a fuel delivery system fault. The unit can also exhibit a duplicate view of the ignition spark so you can visually check ignition system conditions at each cylinder. S ' G says this kit can provide you with more data than OBD-II code-reading devices due to the fact that it can pinpoint where the problem lies+'#8212;whether it's a spark plug, plug wire, mechanical, fuel injection or electrical fault. The company believes this kit can save shop owners time and money by avoiding the replacement of ignition coils that are in good condition.