The spark plug tester is built exclusively from high-quality materials and operates on spark plug connections, diagnosing spark events or spark faults, damaged contacts, bad cables, and more. Heavy-duty construction: Made with durable materials to let you test whether your spark plug is functioning correctly. Save time and money by confirming whether the problem actually lies with the ignition. This handy compact tool helps you see the gap in the spark plug tester to determine if you have inconsistent timing. Provides the highest quality tools to do the job right. Spark plug misfires occur when the sparks jumping the electrode gap are inconsistent in timing, causing the engine to stumble or lose power. Use scenarios: - During routine maintenance on cars, motorcycles, and other spark-ignition engines to verify ignition health. - When diagnosing misfires or power loss to confirm if ignition timing or wiring is at fault before replacing parts. - In workshops or DIY garages to inspect spark plug connections, contact points, and cables for wear.