Trying to figure out why your engine is misfiring or running rough? This AUTOOL spark plug tester makes diagnosing ignition problems a whole lot easier! It's a 12V tool that lets you check the spark on each plug while the engine is running – you just connect it in-line. It's got 5 different test holes and an adjustable height feature, so it can handle a wide range of spark plug types and sizes. The digital display shows the working frequency (from 200 to 9000 RPM) for precise tuning. It works on cars, trucks, motorcycles – basically any 12V gasoline engine. The model is SPT360, it comes with a solid 3-year warranty, and the UPC is 728990664643. Perfect for DIY mechanics, home garages, or even pros who want a quick visual check. Stop guessing and start testing!