Description:Main Unit Size:145*85*60mmMain Unit Weight:220G( Not including Power Adapter)Power Adapter: Input 100-240V AC / Output 12V 1A DCCar Spark Plug Tester Detector with Dual Hole Advantage:Dual Hole Car Spark Plug Tester Detector have two testing holes, you can test two spark plugs meanwhile and and if you suspect any spark plug works improperly you could compare and test to make accurate judgment.Usage: Test spark plug performance and ignition strengthApplication Range: 12V Gasoline vehicles car spark plugsNotice:1. Please Turn Off Power before you place spark plug(It is the most important, please make sure you are safe at first)2. The Spark Plug Tester is a high-voltage detector, so do not touch spark plug with hand at work to avoid danger.Car Spark Plug Test principle:In automobile ignition system, the high-voltage ignition coil generates a high-voltage (10000 volts or more), and the spark plug diverts it formhigh -tension ignition coil into the cylinder engine, spark between the spark plug electrodes will ignite the mixture. The Detector could tell thegood spark plugs from the bad by the strength of the spark.User Manual:1.Place the Spark Plug into tester hole 1 or 2; If you want to compare the new spark plug and old one, place new spark plug into hole 1 and the old on into hole 22.Connect to power supply3.Turn the key switch 4 clockwise to turn on tester, indicator 3 will light up, tester is now working at 1000rpm/min.4. Again turn the key switch 4 clockwise,you can adjust the working frequency between 1000rpm to 5000rpm/min.The higher the frequency, the stronger the spark strength.Package Includes:1pc x Spark plug tester1pc x Power Adapter Return Policy All of our items come with a 30-day free return policy. If you need to return, please contact us, let us know the detailed problem and send us some pictures for confirmation. We reserve the right to refuse any returns for objective reasons. Shipping Policy All of our items are shipped free with tracking numbers. Orders will be shipped within 3 working days upon receipt of payment. Most orders will be shipped within 1 working day. In most cases, shipping takes 8-12 working days.