SJTW vs STW outdoor extension cords: STW wins for real outdoor use

The “J” in SJTW means junior—thinner insulation that’s fine for light indoor use but not built for weather, mud, or being stepped on. STW has a thicker jacket, better abrasion resistance, and won’t crack in the cold. The price difference is usually a few bucks, so skip SJTW if you’re dragging cords through wet grass or leaving them out for a season.