Oura announced the Oura Ring 4, available for $349, which includes several updates aimed at improving health monitoring. The ring features new sensors to track sleep, exercise, heart health, and stress, offering more accurate readings. The Oura app has also been redesigned, offering users a new layout to access detailed health data. Oura Labs, a platform that allows users to test new features, is now available on Android devices after previously being limited to iPhones. Preorders begin Thursday. Shipping is scheduled to start on Oct. 15. A membership plan is required to access full features.