Spark Plug Tester — Heavy-Duty Construction Key benefits Quickly determine whether a spark plug is working so you can avoid unnecessary part replacements and save time and money. Diagnose ignition problems at the spark plug connection: identify weak or missing sparks, misfires, faulty contact points and damaged cables. Portable, easy-to-use tool that makes visual spark checks possible without guesswork. What it does Tests spark plug function by allowing you to observe the spark across the electrode gap. Detects inconsistent timing or weak spark that can cause engine stumbling or loss of power. Works directly on spark plug connections to help pinpoint whether the problem lies in the plug, contact points or wiring. Why it stands out Heavy-duty construction made from high-quality materials for reliable, repeated use. Compact, handheld design for convenient on-vehicle testing and garage work. Built to provide the practical diagnostic information technicians and DIYers need to perform the job correctly. Key attributes Function: visual spark plug testing and diagnosis of spark-related ignition faults. Compatibility: designed to work on spark plug connections (spark plug leads/contact points). Size and portability: small, handheld tool for easy handling and storage. Material and durability: constructed from robust, high-quality materials for long-term use. Performance: reveals inconsistent spark timing and weak sparks that cause misfires and power loss. Typical applications / use scenarios Roadside diagnosis: quickly check a suspected misfire before towing or replacing parts. Routine maintenance: verify new or serviced spark plugs produce a consistent spark before reassembly. Troubleshooting electrical issues: isolate problems at the plug connection to determine whether to inspect contact points or wiring next. Practical, trustworthy, and built for repeated use, this spark plug tester helps you find ignition faults fast so you can take the correct next step in repair or maintenance.