Elegant black ceramic ring by Oura. Smooth polished surface with subtle shine. Simple, modern style suitable for everyday wear. Lightweight and comfortable on the finger. What's Included • 1-year protection plan • Oura Ring 5 - The world’s smallest smart ring Ultra-thin and 40% smaller than Oura Ring 4. Designed to wear like jewelry. Made to move with you, every day. Red and infrared LEDs measure blood oxygen levels Green and infrared LEDs alternate to measure heart rate and heart rate variability 24/7 and respiration rate Digital sensor measures temperature trends Accelerometer tracks movement and activity 24/7 Available on iOS and Android Oura App is available in Arabic, Chinese (Traditional and Simplified), Czech, Danish, Dutch, English, Finnish, French, German, Greek, Hebrew, Hindi, Hungarian, Italian, Japanese, Korean, Norwegian, Polish, Portuguese, Spanish, and Swedish. Supports metric and imperial units of measurement Integrates with 100+ apps