The Oura Ring 4 in Silver, Size 5 is a discreet, all-titanium smart ring with Smart Sensing that adapts to your finger — tracking sleep, HRV, blood oxygen, temperature, and stress. Up to 8 days of battery, no screens, no buzz. Auto-detects 30+ activities and gives a daily Readiness Score Pairs with the Oura app on iOS or Android. First month of membership included; $7.99/mo after This description was generated by AI and reviewed for accuracy.