Our heavy duty booster cables are 1 gauge (AWG) welding type, stranded copper, oil and abrasion resistant, and are able to maintain flexibility at -94 degrees and +198 degrees Fahrenheit.  The conductor is crimped and soldered to the clamp, and is capable of withstanding a 500 lb. axial load, without disengagement from the clamp.  Booster cables now come in 12 foot, 16 foot, and 25 foot lengths.  Each clamp is made from a .064" thick solid copper sheet.  The clamp jaws are serrated, and clamps are assembled with a heavy duty, high tension spring to ensure a good connection to the battery terminal.  The color coded handle grips are molded non-rigid polyvinylchloride.  Each clamp and cable has a 600 amp minimum current rating.