Precise ignition status detection - Uses precise measurement functions to accurately detect the ignition status of your vehicle's spark plugs and quickly identify ignition problems. Inline tester with spacer - Comes with a spark plug spacer to ensure excellent performance when testing, using an inline spark plug tester design. Easy to use - The inline spark plug tester is user-friendly and requires no special knowledge for operation; it also functions as a spark plug coil detector. Versatile car test pen - This versatile tool can be used to test and repair various components and serves as a car spark plug tester when needed. Use scenarios - Routine maintenance: Use to confirm spark plug ignition status and quickly identify potential ignition problems during regular service. - Troubleshooting ignition issues: Test and verify ignition coil and spark plug performance with the inline tester and coil detector to diagnose misfires or weak ignition. - General electrical testing: Use as a general purpose test pen to test and repair various car components as needed.