The OnePlus 8T Concept is a wild new idea from OnePlus, a phone that changes color on the back in response to breathing. The phone, unveiled today by OnePlus, showcases the company's new OnePlus Gaudí design studio while also showcasing next-generation technology and design.

The OnePlus 8T was introduced in October and did not change much from the original OnePlus 8, but it did gain the OnePlus 8 Pro's 120Hz display and a new super-fast 65W wired charging system. However, the 8T concept is so different that one can hardly tell it's the same phone, except for the logo and the placement of the rear camera.

The design of the 8T concept consists of a curved body with a color-changing wave pattern on the back. This pattern is made of a metal oxide film, which changes between silver and dark blue depending on the current flow.

This color-changing feature is aided by another major new feature: millimeter wave radar built into the rear camera module. It uses the same signal that powers mmWave 5G to detect and track user movement. mmWave sensors have several different functions, as shown in the video provided by OnePlus. It can be used as a type of gesture control, and the color on the back changes to act as one large notification light.

More interestingly, OnePlus has shown that this sensor can detect the breathing of others. The demo only shows that the phone measures the number of breaths per minute and the color on the back changes to reflect how fast one is breathing. If OnePlus extends this feature, perhaps in conjunction with the teased OnePlus Watch, it could become a useful health monitoring application.

Some phones, like the Google Pixel 4 and Huawei Mate 40 Pro, have been experimenting with radar functionality for some time. While these systems can work well, their applications are currently quite limited and the controls can be difficult to use; the OnePlus radar works smoothly in the video, but we do not know how well it would work in a real-world scenario.

The last OnePlus concept, Concept One, appeared at CES 2020. In our hands-on, we were fascinated by the phone's color-shifting glass that hides the rear camera, the same technology that makes the new concept's rear color change possible. 90Hz displays and pop-up selfie cameras are a bit dated now, but still very Still, it is very stylish and undeniably unique.

The concept is a bit like an actual phone, and if OnePlus can get these features to work reliably, it would be nice to see them in the OnePlus 9 and later flagship models. Sadly, however, the OnePlus 8T concept is likely to remain just that, a concept, for the time being.