Heavy duty 16 Gauge. Our copper wire is soft drawn & annealed for maximum flexibility under full load. Heavy duty outdoor jacket that is water and flame resistant for added protection. Heavy-duty molded on 15A-125V plugs and connectors. 5/8 strain reliefs in back of plug and connectors prevent ends from pulling away from cord body. Both plugs have a built in amber neon light which indicates that there is power in the cord and outlet.