This new Harbor Freight In-Line Ignition Spark Checker (Item 04424) is a diagnostic tool designed to test for spark in gasoline engine ignition systems. It connects between the spark plug and the spark plug wire to help identify issues like fouled plugs, faulty wires, or coil problems. This is a practical purchase for mechanics, DIY auto enthusiasts, or anyone troubleshooting small engines on lawnmowers, motorcycles, or other equipment. The item is listed as new and may include free shipping; check the listing for full details on compatibility and any included accessories. In-Line Ignition Spark Checker From Harbor Freight (Item. 04424) New. Condition: New, Made in China. Listed at 3.00 USD. The In-Line Ignition Spark Checker from Harbor Freight (Item. 04424) is a diagnostic tool designed to check the spark ignition system in passenger vehicles. This unit includes a ground wire and is manufactured in China. It is a single unit designed to help with troubleshooting ignition issues in automobiles. With the Harbor Freight brand reputation and specific manufacturer part number, this spark checker is a reliable and efficient tool for diagnosing and maintaining vehicle ignition systems. Package has yellowed.