A simple test device to determine the spark voltage and ignition system condition. The C Spark is installed between the coil and the distributor, the distributor and a plug, or a plug wire and ground. This tool indicates problems in the ignition system; low battery, defective coil, bad condenser, resistive points, wiring, etc. An additional use of the C Spark is to clear and start engines that are flooded with gasoline. Instructions for use are included. A genuine Nu-Rex product.