Lisle 20580 InLine Spark Tester w/Coil On Plug Wire, One Size, Factory

Connect the tool between the spark plug and the plug wire. The short wire is double ended to offer a straight boot and a 90degree boot on one tool. With the engine running, the tool flashes a mirror image of the ignition spark. The additional 7 extension plug wire is used on coil on plugs that are recessed and hard to reach.