The Oura Ring 4 introduces advanced "smart sensing" technology, significantly improving data accuracy and comfort. This new system utilizes 18 signal pathways (up from 8 in the previous model) to collect health data, with an algorithm that dynamically selects the most reliable pathway in real-time12. Key enhancements include:

• 120% improvement in blood oxygen sensing signal quality

• 15% more accurate breathing disturbance index

• 7% fewer gaps in daytime heart rate data

• 31% fewer gaps in nighttime heart rate data3

These improvements, combined with the ring's new titanium interior and recessed sensors, result in a more comfortable fit and more consistent data collection, addressing previous issues with data gaps caused by ring movement14.

The Oura Ring 4 introduces a significantly expanded size range, now offering options from size 4 to 15, compared to the previous generation's 6 to 13 range12. This expansion makes the Oura Ring 4 more accessible to a wider variety of users, accommodating both smaller and larger finger sizes. The new sizing options include:

• Smaller sizes: 4 and 5, catering to those with more petite fingers

• Larger sizes: 14 and 15, accommodating users with larger hands

• Existing range: 6 to 13, maintained from the previous generation

It's important to note that the sizing for the Oura Ring 4 may differ from previous models, with the new rings running approximately half a size larger than standard US ring sizes2. For example, an Oura size 10 corresponds to about a US size 9.5. This change in sizing emphasizes the importance of using Oura's sizing kit before ordering to ensure a proper fit3.

The Oura Ring 4 features a significant design upgrade with its all-titanium construction, including both the exterior and interior of the ring12. This marks a departure from the previous generation's epoxy interior, enhancing durability and potentially improving sensor accuracy2. The new design eliminates the raised sensor domes found in earlier models, resulting in a sleeker and more comfortable fit3.

Key design improvements include:

• Fully rounded shape, removing the flat edge present in some previous models2

• Recessed sensors that reduce the interior protrusion from 1.3mm to just 0.3mm2

• Expanded size range from 4-15, compared to the previous 6-13, accommodating a wider variety of finger sizes23

• Available in brushed silver, black, gold, rose gold, silver, and stealth finishes1

These changes not only enhance the ring's aesthetics and comfort but also contribute to improved durability and potentially more accurate health tracking capabilities12.