That 'W' means it's safe for outdoor use.

Yes—the “W” in SJTW stands for “weather-resistant.” That means the cord’s jacket is built to handle moisture, UV light, and temperature swings better than a standard indoor cord.

SJTW is a common rating for outdoor extension cords. The letters break down like this: S = service cord (600V), J = junior (300V), T = thermoplastic (vinyl jacket), W = weather-resistant. Without the W, you’re looking at an indoor-only cord that will degrade fast in rain or sun.

If you’re using a cord outside, even occasionally, get the W. The difference in price is small. The difference in safety and lifespan is not.

Don’t be the person who runs a non-W cord through a puddle and wonders why the breaker trips.