Smart ring maker Oura is facing a proposed class action lawsuit alleging it misled consumers about the accuracy of its sleep-tracking features. Filed on Thursday by Clarkson Law Firm in San Francisco, the complaint claims Oura rings cannot actually measure the physiological signals needed to assess sleep quality or stages, relying instead on AI-generated estimates that the lawsuit says have "a coin flip's chance of being correct." This matters because Oura markets its rings, priced from $300, as offering clinical-grade insight into sleep, and the case comes after years of users complaining online that the device's readings did not match how they actually felt.

The lawsuit argues that determining sleep stages genuinely requires equipment such as scalp electrodes and eye sensors found only in clinical settings, since "sleep happens in the brain, not on one's finger." It alleges Oura advertised "unparalleled accuracy," at one point citing 79% accuracy and more recently claiming 95% sleep-staging accuracy versus clinical sleep labs. The complaint seeks an injunction to stop the company misrepresenting its products, along with restitution for affected customers. Oura had not responded to a request for comment at the time of publication.