The Oura Ring 4 combines cutting-edge technology with minimalist design to deliver powerful, science-backed health insights - all from a ring you’ll barely notice you’re wearing. Crafted from durable, hypoallergenic titanium, it continuously tracks your sleep stages, heart rate, blood oxygen levels, activity, recovery and menstrual cycle. It even measures body temperature and detects stress signals to help you better understand your readiness and overall well-being. Water resistant up to 100 meters and weighing just 3.3–5.2 grams, the Oura Ring is made for all-day wear and active lifestyles. Up to 8 days of battery life per charge. The ring comes with a personalized sizing kit to ensure the perfect fit before your final ring is shipped. Note: An active Oura Membership (sold separately) is required to unlock full access to insights, trends, and recommendations through the Oura App.