Car Spark Plug Testing Principle:
In an automobile ignition system, the high-voltage ignition coil generates a high voltage (10,000 volts or more), and the spark plug diverts its shape
High-voltage ignition coil in the cylinder engine, sparks between the spark plug electrodes will ignite the mixture. The detector could tell that
Good sparks plug out the bad ones by the strength of the sparks.

Car Spark Plug Tester With Note:
1. Please turn off the spark plug tester before inserting the spark plug
2. The Spark Plug Tester is a high-voltage detector, so do not touch the spark plug with your hand when working to avoid danger.

Auto Spark Plug Tester User Manual:
1. locate the spark plug in tester hole 1 or 2; If you want to compare the new spark plug and the old one, place the new spark plug in hole 1 and the old one in hole 2
2. Connect to the power supply
3. Turn the key switch 4 clockwise to turn on the tester, display 3 will light up, tester is now working at 1000 / min.
4. Again turn the key switch 4 clockwise, you can set the working frequency between 1000rpm to 5000 / min.
The higher the frequency, the stronger the spark strength.

Package Includes:
1pc x 16mm Socket spark plug tester
1pc x Power Adapter
1pc x EU plug