Quickly diagnose problems with all ignition systems,Connect the tool between the spark plug and the plug wireNormal sparks of fire gauges as"purple blue and 2cm straight line,"if the ignition coil is bad when the color is red or curveUse this ignition spark tester to check the condition of the ignition system at each cylinder without going to expensive mechanics.The spark tester connects between the spark plug and spark plug wire in seconds to troubleshoot dirty spark plug connections,defective points and bad cables or connections.Connects in seconds.Colour:Blackmaterial:plasticSize:Jumping distance is about 0.8-1.5cmPackage Contents:2pcs x Spark plug testerOnly the above package content, other products are not included.Note: Light 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.