🚘 Light Design - This spark plug tester tool is equipped with a high brightness neon bulb that accurately reacts to spark plug problems. You can quickly find out if the spark plug connections, contact points and cables are working properly, and you can replace faulty parts in time to avoid erratic engine operation. 🚘 Durable and - Our spark plug testers also offer outstanding durability. The shell is made of superior quality ABS material, which is hard and unbreakable, the inner part is made o