Bullet Points: 1、Double-hole Spark Plug Tester: In order to see the performance of the spark plug more clearly, the spark plug tester has a double-hole test function. Simply put a spark plug and the spark plug to be tested into the test holes to test the performance of the spark plug quickly and accurately. 2、Adjustable Working Frequency Spark Tester: The working frequency of the spark tester for small engines is 500-6000rpm. Its working frequency can be adjusted by knob, which is very convenient. 3、Test Principle: In the automobile ignition system, the high-voltage ignition coil generates high voltage, the spark plug transfers the high-voltage ignition coil from the high-voltage ignition coil to the cylinder engine, and sparks are generated between the electrodes of the spark plug. Ignite the mixture. The detector can distinguish the quality of the spark plug by the spark intensity. 4、Durable Material: Our spark plug tester is made of high-quality ABS material, which is safe and tasteless, moisture-proof and high-temperature resistant, not easy to break, environmentally friendly and durable. 5、Satisfactory Service: You can consult us at any time if you have any questions, and we will answer patiently. We will try to provide you with a happy shopping experience and solve your problems asap. Features: 1. Adjustable Working Frequency 2. Double Test Hole. 3. Prtoctive Cap. Specification: Frequency adjustment range: 500-6000 rpm Voltage: 100-240V Net weight: 354g Packing List: Spark plug tester *1 Note: 1. Due to the lighting effects and shooting angles, there is a color difference in the product, please understand. 2. Due to manual measurement, there is a tolerance in the product size.