Car Spark Plug Tester Pen is a compact auto test tool that helps you verify spark presence quickly and reliably. - Quick spark indication: Turn the engine over; if ignition is reaching the cylinder, the tester light glows, giving a fast yes/no signal on spark. - Easy operation: Remove the rubber boot from the spark plug, insert the tester, then place the tester boot on the plug. No tools required. - No-start diagnosis: When the engine won’t start, use this tester to answer the question does it have spark. - Durable construction: Made of high-grade material for lasting use in regular automotive work. - Portable and practical: Car Spark Plug Tester Pen is compact and easy to carry in a toolbox or on the road. - Compatibility: Designed to work with common automotive spark plugs. Use scenarios - In-shop diagnosis of misfire or no-start: quickly verify if spark is reaching each cylinder. - On-the-road troubleshooting: perform a fast spark check before towing or more extensive ignition diagnostics. - Routine maintenance: confirm ignition system status during tune-ups or inspections.