【Wide Application】: The in-line spark plug tester is an essential diagnostic tool for any engine with spark plugs, suitable for all internal and external combustion engines, cars, trucks, motorcycles, lawnmowers, chainsaws, trimmers, snow blowers, generator engines, etc. Spark plug testers are suitable for all domestic, commercial, mechanical, industrial and commercial uses where spark plugs are used in engines.【High-quality materials】: The probe of this spark tester is made of high-quality plated rod, the optical housing is made of environmentally friendly acetate plastic, and it adopts a straight rubber sheath and cable. High-quality materials resist rust and corrosion even in high and low temperature environments.【Easy to use】: Easily determine which cylinder has a problem with this product; Just connect the spark plug detector tool between the spark plug and the spark plug wire, then start the engine; if there is a spark, the inline spark tester will reflect the spark by lighting up; if you are checking a no-start situation, ask a friend to start the engine so you can observe signs of spark. 【Light Indication】: The spark plug engine ignition tester kit is equipped with a high-intensity neon bulb inside, which can easily tell if the ignition wire is intact by flashing. With the help of the indicator light, the spark plug ignition tester can determine which cylinder is causing the problem and find the exact cause.