1.Size Before You Buy - Ring sizes are different from standard ring sizes.It is strongly recommended to measure the size before purchasing. Please according to the wearing instructions on the details page, first measure your finger circumference, then calculate the inner diameter of your finger, find the corresponding ring size number and select it. 2.All Day Monitoring -The Smart Ring is fully integrated with monitoring, fitness tracking and sleep quality analysis. It monitors your heart rate, oxygen saturation, and blood oxygen 24 hours a day, making sure you know your at all times.The Fitness Ring connects to your phone via Bluetooth to track detailed information.Data can be easily viewed through the mobile app without any subscription fee. 3.Movement Index -The smart ring tracks your activities throughout the day with high precision. For example, the Fitness Ring tracks your steps, distance walked and calories burned. In addition, the Smart Ring features different exercise modes such as walking, running and cycling. Analyze mapped routes and detailed workout data to improve your performance and exceed your limits. 4.Sleep Index -The sleep tracking feature makes it an ideal companion.Derived to help you understand the various sleep stages such as deep sleep, REM sleep, Light sleep and being awake, during different stages of sleep, different metabolic processes of the body occur for growth, repair, restoration, and maintenance.