Century Wire and Cable heavy-duty Pro Style extension cords have become the industry standard for durability and safety. 

Century Wire and Cable uses soft-drawn, bunch-stranded 100% copper conductors for maximum flexibility.  In addition, the heavy-duty plugs are molded with large strain reliefs that prevent the ends from pulling away from the body. The cords are shielded with cold weather insulating and jacketing compounds, which provides great results in weather below freezing point, as well as flexibility in the winter.