【Wide Application】: The in-line spark plug tester is an essential diagnostic tool for any engine with a spark plug, it is suitable for all internal and external combustion engines, cars, trucks, motorcycles, lawn mowers, chainsaws, trimmers, snow blowers, generator engines, etc. The spark plug tester applies to all households, businesses, mechanics, industrial and commercial applications that use spark plugs in engines. 【Premium Materials】: The probe of this spark tester is made of a plated shaft high quality, the optical housing is made of environmentally friendly acetate plastic, and the straight rubber sheath and cable. High-quality materials are resistant to rust and corrosion even in high and low temperature environments. 【Easy To Use】: Easily determine which cylinder is the problem with this product; Simply connect the spark detector spark plug tool between the spark plug and the spark plug wire, then start the engine; If sparks are sent, the in-line spark tester will reflect