Heavy-duty 4000-amp automotive booster cables (also known as jumper cables) are essential emergency tools designed to jump-start vehicles with dead or weak batteries by safely transferring electrical current from a working battery.Key Features & SpecsAmperage Rating: Marked for heavy-duty 4000-amp capacity, suitable for cars, SUVs, vans, and larger engines.Design & Storage: Packed in a round, zippered plastic/canvas carry case with a clear top window.Clamps: Features insulated handles with strong-grip metal spring clamps for secure terminal contact.