Oura announces new smart ring with updated design and new sensors for $349 CNBCOura just launched its latest smart ring. Apple and Samsung are coming for it Yahoo! VoicesThe Oura Ring 4 has slimmer sensors, increased accuracy, and more sizes The VergeOura Ring 4 First Take: More Titanium, Better Accuracy and Longer Battery Life CNETThe New Oura Ring 4 Will Be Thinner and More Capable Than Ever WIRED