The Oura Ring 4 is a smart health and sleep tracker designed for unisex adults. It features a 240 x 240 display resolution, a sleek black color, and a size of 14. This activity tracker provides heart rate and distance measurements, as well as tracking sleep quality with its built-in sensors for SpO2 and accelerometer. With a battery life of up to 7 days, the Oura Ring 4 is designed for both indoor and outdoor use, making it a versatile tool for those looking to monitor their health and sleep patterns. Compatible with iOS and Android operating systems, this smart ring offers a comprehensive set of features for optimal performance.