A viral social media post recently sparked curiosity over a common towel feature: that raised line running across many bath towels. Some joked it was a “face-to-butt separator” or a “racing stripe,” but the real explanation is more practical.

That line is called a dobby border. Though it may look decorative, it plays a key role in durability and function. Textile experts explain that the dobby border helps towels maintain their shape and resist fraying after repeated washes.

One major benefit of the dobby border is reinforcement—it strengthens the towel’s structure, especially along the edges, which are most prone to wear. It also helps the towel stay evenly shaped and prevents the ends from becoming bulky.

Beyond function, dobby borders provide space for subtle design or branding, adding texture or logos without sacrificing comfort or absorbency.

So next time you reach for a towel, take a second look at that small stripe. It’s not just for looks—it’s a smart design element that helps your towel last longer and work better.