Features and Benefits: * Use to quickly trouble shoot ignition system * Device is "hands-free" * Connects in-line between spark plug and spark plug wire * Technician can visually check condition of ignition system at each cylinder * Frequency and intensity of flash indicates whether there is an ignition system problem or a fault in the fuel delivery system The in-line ignition spark checker has a clear body that allows the flash to be seen in outside/sunlight conditions. The body is made of heavy duty plastic and is chemical resistant and is ideal for any technician"s tool box. 1 year warranty on material and workmanship.