The Oura Ring Gen 4 Size 10 in Silver is a new, unopened activity tracker designed for both indoor and outdoor use. It provides heart rate measurement and has a battery life of up to 7 days. The ring is equipped with an accelerometer sensor, a 2.4X external display with a resolution of 240 x 240, and features a sleep tracker. Made of metal and manufactured in Estonia by the brand Oura Ring, this unisex activity tracker is compatible with Android operating systems and comes with a 1-year manufacturer warranty.