The Oura Ring 4 has slimmer sensors, increased accuracy, and more sizes The VergeOura announces new smart ring with updated design and new sensors for $349 CNBCOura Ring 4 First Take: More Titanium, Better Accuracy and Longer Battery Life CNETOura Ring 4 debuts slimmer design, additional sizes, and improved sensing starting at $349 TechCrunchThe New Oura Ring 4 Will Be Thinner and More Capable Than Ever WIRED