The conductors used in Century Wire extension cords are 100% copper conductors for maximum amperage transmission. This means that more of the power that enters one end of the cable is delivered at the other. This increase in efficiency means less heat and less voltage drop, even over long distances.
Multiple bunch stranded conductors (the more, the better) are what gives extension cords their flexibility and that makes them easier to coil and less likely to break of kinked or knotted.
Harrison Bros. Inc.