The U.S. Patent and Trademark Office (USPTO) on Thursday published an Apple patent application that describes a modification to the Apple Watch’s design that could ultimately make future units thinner. The patent application, which was earlier discovered by Apple-tracking site AppleInsider, is called “Band attachment mechanism with haptic response.”

The technology described in the patent application would allow Apple to bundle vibrations and other “haptic feedback” features into the Apple Watch wristband instead of bundling it inside the smartwatch’s case. That would allow Apple to remove the so-called Taptic Engine that controls haptic feedback and reduce Apple Watch case thickness.

Get Data Sheet, Fortune’s technology newsletter

Apple Watch comes with the Taptic Engine beneath its screen. The small component responds to user inputs and app commands and delivers a vibration and movement that users can feel when wearing the device. While Apple (AAPL) has no interest in removing the feature, getting it out of the Apple Watch case could give the company more design flexibility. But because the Apple Watch is only a timepiece with a wristband, there are few other places the component can go.

That’s apparently why Apple is exploring the possibility of placing haptic feedback components in the Apple Watch wristband.

“Many portable electronic devices continue to decrease in size while the number of uses and functions of the electronic devices can remain the same or increase,” Apple writes in the patent. “For example, some cellular phones and digital music players are contained within small and compact housings that include electronic circuits and components that provide a user with a wide range of applications and functions. Space can therefore be an issue when including or adding additional components, circuits, and functions to a portable electronic device.”

For more about Apple Watch, watch:

In order to deliver the feature, however, Apple will need to bundle sophisticated components—including electromagnets, piezoelectrics, and electroreactive polymers—into the wristband. All of those components will cause the band to move side to side and perhaps even up and down to register a sensation with the user through the strap.

All the while, Apple could make Apple Watch—which is designed not only to tell time but also be used as an activity tracker—a bit sleeker on the wrist.

That said, this is only a patent application, and it’s unknown whether Apple will actually deliver the technology in a future Apple Watch update. Like other major companies, Apple files for a slew of patents and some never find their way to its hardware. The company won’t comment on any future plans until its announcements are official.