The new ring model also includes a slightly different internal design, with smaller sensor bumps. This means the two rings of the same nominal size will fit completely differently on the same finger.

The gen 4 gathers the same data but is sometimes more accurate, comes in a wider range of sizes, and has a smooth interior rather than the sensor bumps of ... to know your ring size to order ...

Previous generations of Oura rings had three clear plastic bumps for the ... the body of the ring to make it thinner and more wearable. It also comes in a much bigger size range, with sizes ...

Circular's new smart ring, the Ring 2, has an FDA-cleared AFib detection algorithm It can be sized using your smartphone, with no need for a plastic sizing kit Battery life runs for up to eight ...