ACCURACY - SMART SENSING - Oura tracks over 30 biometrics, including sleep, activity, stress, heart health, and women’s health metrics. Oura Ring 4 is powered by Smart Sensing, which adapts to you — delivering accurate, continuous data, day and night. LONG LASTING BATTERY - With up to 8 days of battery life, no screens and no vibrations, Oura Ring 4 allows you to focus on the present. From a workout to a night out — you’re free to forget it’s on. Until you start getting compliments. DESIGNED FOR 24/7 WEAR - The updated design of the Oura Ring 4 is more comfortable, fits better than ever, and is water resistant. The first all-titanium smart ring combines exceptional durability with a gentle touch, even for sensitive skin. SYNC WITH YOUR FAVORITE APPS - Compatible with iOS and Android — Oura seamlessly integrates with over 40 apps including Apple Health, Google Health Connect, Natural Cycles, Flo, Strava, & more. HSA/FSA ELIGIBLE - We can accept HSA or FSA funds for the following: Oura Ring, additional chargers, and shipping.