To Test spark plug performance and ignition strength, apply to 12V Gasoline vehicles car spark plugs.Adjustable double hole car spark plug tester detector Ignition Plug Analyzer Diagnostic Tool Car 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 strength Application Range: 12V Gasoline vehicles car spark plugs Gasoline Car Spark Plug Tester Product Parameters:Power Adapter: Output 12V 1A DC Plug Type:EU Plug,it applies to Indonesia, Germany, France, Spain, Italy and so on. Plug Type:US Plug, it applies to Canada, India, Mexico, Thailand, Taiwan, the , the Philippines and so on. voltage: AC100-240V Colour:As Shown Material:ABS Car Spark Plug Tester Using Note: 1. Please Turn Off Power before you place spark plug 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 Tester User Manual: 1.Place the Spark Plug into tester hole 1 or 2; If you want to compare the spark plug and old one, place spark plug into hole 1 and the old on into hole 2 2.Connect to power supply 3.Turn the key switch 4 clockwise to turn on tester, indicator 3 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. Package Contents: 1 * Car Spark Plug Tester 1 * US Plug Adapter 1 * EU Plug Adapter 2 * Gasket Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.