The Oura Ring is a wearable sleep tracker and heart rate monitor that can give you useful insights into what's going on in your body. In fact, the Oura Ring is being used in research studies for its potential ability to detect COVID-19 infections before symptoms appear. Wirecutter staff writer Justin Redman tested the Oura Ring and dug into the data to see how effective this tiny device really is, and whether it's worth the steep price. | Wirecutter