The Oura Ring 4 Ceramic Petal in Size 8 is an activity tracker designed for unisex adults who engage in running and jogging. It provides heart rate and calorie measurements, with a battery life of up to 7 days. The ring features a sleep tracker, accelerometer sensor, and a display resolution of 240 x 240. Made from a combination of aluminum, titanium, and metal, this fitness technology offers a sleek and durable option for indoor and outdoor use. It is operated by batteries and comes with a 1-year manufacturer warranty.