4th gen Oura Ring only worn for 2 weeks. (Requires a subscription to the Oura app) OURA RING is the next evolution of the revolutionary smart ring, designed to help you get up close and personal with your health. Oura Ring 4 is built around a breakthrough sensing technology, Smart Sensing, which is powered by an algorithm that works with research-grade sensors to dynamically adapt to the finger and deliver accurate and continuous data, day and night.