Oura Ring 4 Sleep and Health Tracker [Gold Size 9]

The Oura Ring 4 packs 18 sensors into a slim titanium ring to track sleep stages, heart rate variability, SpO2, and women's health insights 24/7. With up to 8 days of battery life and the built-in Oura AI Advisor, it delivers personalized daily health guidance on iOS and Android. Prime Day drops the Gold size 9 to $259, a 48% savings from the usual $499.