Simple to use ignition diagnostic tool - How it works: remove the rubber boot from the spark plug, insert the tester, and place the tester boot on the plug. The tool sits between the spark plug and the plug wire for quick testing. - Key function and benefits: quickly diagnose ignition system problems and determine presence or absence of spark. Helps identify no-spark conditions fast, saving time during troubleshooting. - Detects common issues: finds dirty spark plugs, defective points, bad cables, or loose connections that can cause misfires or starting problems. - Practical compatibility and performance: designed to connect between standard spark plugs and plug wires, enabling fast checks without extensive disassembly. Provides clear, practical results to guide repair decisions. Use scenarios - No-start or hard-start condition on cars, motorcycles, or small engines: verify whether spark is reaching the plug to isolate ignition versus fuel delivery issues. - After replacing spark plugs or ignition components: confirm that the new components are delivering a proper spark and wiring is functioning correctly. - Intermittent misfire or rough running during maintenance: test plug-to-wire connection points and wiring integrity to pinpoint fluctuating ignition faults.