SJTOW is better, but SJTW is fine for most outdoor use.

They’re both outdoor-rated. The difference is the oil resistance.

“SJ” means junior service cord (300 volts), “T” means thermoplastic, “W” means weather-resistant. “O” adds oil resistance. So SJTOW can handle being near gas, oil, or chemical spills without the jacket getting brittle or cracking. You’ll see it in garages, construction sites, or around lawn equipment.

For normal yard work — hedge trimmers, string lights, an electric mower — plain SJTW is perfectly fine. Don’t overthink it. Just make sure it’s actually stamped with a “W”, because that’s the part that matters for rain and UV.

If you’re running a cord near a car, a generator, or gas-powered tools, step up to SJTOW. The extra few bucks saves you from replacing a melted cord next summer.