Spark Plug Tester Dual Hole Ignition Analyzer Diagnostic Tool 12V Gasoline Car

Car Spark Plug Tester Dual Hole Adjustable Ignition Spark Plug Analyzer Detector. Place the Spark Plug into tester hole 1 or 2; If you want to compare the new spark plug and old one, place new spark plug into hole 1 and the old on into hole 2.