ITEM NAME:Spark Plug Tester Automotive Ignition System In-line Coil Tester Test Auto Tool Descriptio n Description: Made of premium material for maximum durability. Designed for test spark plug performance and troubleshoot internal combustion engines. You can quickly and easily diagnose whether your car power system is working properly. The spark tester is connected between the spark plug and the spark plug wire in seconds to solve problems dirty spark plug connections, bad points and bad cables or connections. Provides a secure, reliable way to diagnose faults, convenient, cost-effective, and time-saving. Specifications:.(The spark tester is connected between the spark plug and the spark plug wire in seconds to solve problems dirty spark plug connections, bad points and bad cables or connections. 5) If ignition circuit is complete, bulb will flash.