2 Pack in-line Spark Tester Tool - Adjustable Ignition System Coil Test Coil-on Plug

Perfect diagnostic tool for accurately identifying a weak spark in minutes, simple to use, test for no-start conditions It is the resistance to spark 10k, 20k, 30k and 40k ohms, white lettering can make you read the gap measurement easier Groud the clip to the engine. Put the other end in the spark plug wire. Read the length on the spark through the little window. The longer the spark gap the stronger the coil The standard plug wire tip and can be unscrewed so the tester can be used on small engines and some motorcycles.