The Oura Ring 4 is a versatile activity tracker designed for both indoor and outdoor activities. Featuring a display resolution of 240 x 240, this black ring uses batteries for power and can track heart rate with its built-in accelerometer. With a sleek design made from titanium and metal, it is suitable for iOS and Android operating systems. The Oura Ring 4 also includes features for tracking sleep patterns and is perfect for running and jogging activities. Made by the brand Oura in the United States, this unisex activity tracker has a one-year manufacturer warranty and up to 7 days of battery life. Item is brand new and unopened!