The Oura Ring Gen 4 Black in size 10 is a high-tech activity tracker designed for indoor and outdoor use. It provides detailed measurements of heart rate, calories, and distance traveled, as well as features such as Bluetooth connectivity, temperature monitoring, and a rechargeable battery. The ring is made of titanium and is water-resistant, making it durable and reliable for various fitness activities. With a stylish silver design and a display resolution of 240 x 240, the Oura Ring 4 is a sleek and functional tool for tracking your health and fitness goals. Got it refurbished from Oura with a replacement