This ring is brand new in the box, never worn because I ordered the wrong size and it's too small. REVOLUTIONARY SMART RING: Fitness tracking. Measures detailed sleep quality, daytime stress, live heart rate and more with the Oura Membership. New members get the first month free, then it’s $5.99/mo. You can register for Oura Membership on the Oura App. MORE ACCURATE BY DESIGN: Your finger provides the most accurate pulse reading, making your health data and insights more personal than ever. Oura Ring’s research grade sensors monitor over 20 biometrics with precision. 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. 5-7 days of battery life.