Features: It comes with two test holes, which can test two spark plugs. Designed to test spark plug performance and ignition resistance. Suitable for 12V gasoline vehicles. Plug and play, easy to use, durable and reliable. Specifications: Power supply: input 100-240V AC; output 12V 1.5A DC Host weight: 190G (power adapter not included) Size: about 145*85*60mm Detection ports: 2 How to use: 1. Insert the spark plug into the test hole 1 or 2. (Note: If you want to compare the old and new spark plugs, please insert the new spark plug into hole 1 and the old spark plug into hole 2.) 2. Insert the power adapter into the host socket. 3. Turn the knob clockwise. When powered on, the top light will light up for charging. At this time, the indicator light 3 is on, and the tester is working at 1000 rpm. 4. Turn the key switch 4 clockwise again, and the frequency reaches 2000 to reach the ignition state. The higher the frequency, the stronger the spark plug. (Note: The higher the frequency, the stronger the spark intensity.) Note: 1. Please turn off the power before inserting the spark plug. 2. Connect the power supply, the red light is on. 3. After the green light is on, it belongs to the working mode. 4. Do not touch the spark plug with your hands during work to avoid danger. 5. If it is suspected that the spark plug is not working properly, it can be compared and tested to make an accurate assessment. Contents of delivery: 1 pc spark plug tester 1 pc power adapter