1.【High-quality materials】: The spark plug tester is made of high-quality plastic and metal, which is durable. It is not easy to age, has good toughness, hardness and balanced mechanical properties, low impact resistance and high product quality. The double-headed flexible tool with internal bulb can be used for many years and can be interchanged with the transparent housing. 2.【Easy to use】: You only need to connect the metal end of the tester to the spark plug coil and start the engine. When the ignition cable is intact, the indicator light will illuminate. Use this ignition spark tester to check the condition of the ignition system of each cylinder without expensive mechanical maintenance. 3.【Easy to observe】: Transparent observation window, easy to observe the overlap situation, confirm whether it is normal, easy to use. Just connect the tester between the spark plug and the spark plug cable. When a spark is emitted, the tester reflects the spark and ignites it. Look for dirty spark plugs and damaged points. 4.【Wide range of applications】: The engine coil tester is essential for troubleshooting all internal combustion engines and external internal combustion engines, such as cars, trucks, motorcycles, lawn mowers, chain saws, trimmers, snow blowers, generators, etc. 5.【Convenient and safe tool】: Lightweight and easy to carry, the ignition tester can be put in the tool bag. It saves time while providing a safe way to identify sparks.