[Spark Plug Tester For Small Engines Test Spark Plug Performance]The spark tester mainly tests the performance of the spark plug by simulating the ignition of the car, thereby deciding whether to replace the spark plug. [Dual Holes Spark Plug Tester]In order to be able to see more clearly whether the performance of the spark plug is good, the spark plug tester has a dual-hole test function. Just put a brand-new spark plug and a spark plug to be tested into the test hole respectively, and the performance of the spark plug can be tested quickly and accurately. Test hole inner size: 10mm. [Adjustable Working Frequency Spark Tester]The working frequency of the spark tester small engine is 500-6000rpm. Its working frequency can be adjusted through the knob, which is very convenient. [Ignition Tester For 12V Gasoline Vehicles Car Spark Plugs]This spark plug tester is suitable for most 12v gasoline car spark plugs. Cannot be used for lawn mowers and chainsaws. If you are not sure whether it is suitable for your spark plug, please contact us before buying. [Coil Tester With A Protective Cover]In order to make the process of use safer, the spark plug tester comes with a transparent protective cover.