Battery jumper cable is an emergency tool that should be carried around in your car in case of a failed battery. It’s made from high quality Copper, long lasting. If you experience a failed battery, all you need to do is connect red (+) positive jumper cable to the (+) positive battery terminal of the battery and the black (-) negative jumper cable to the (-)negative battery terminal of the battery, follow the same process with the supporting battery or car and go ahead to start your car.