The Oura Ring, including the latest Oura Ring 4, features a sleek and stylish design. But you may notice that on some models, including the Oura Ring 4 and Gen 3 Horizon, there is a small notch, or dimple, that runs up and down vertically on one side. You might think it’s just for style reasons or wonder if it serves a specific purpose. The answer is the latter. The notch is there for a reason.
This goes back to how smart rings work. They have photoplethysmography (PPG) sensors on the underside that come into contact with your skin. These sensors emit LED light which, when it hits your skin, is absorbed by the blood pumping through your vessels. By detecting changes in the absorption of this light throughout the day, even minute by minute, the smart ring can capture data like your heart rate. It also uses red light absorption to measure blood oxygen. When your heart contracts, blood volume increases and when it relaxes, it decreases. Some smart rings also have temperature sensors to monitor temperature rhythms. And of course, there’s an accelerometer that detects your movements in different directions. To accurately capture all of this data, the sensors need to be properly positioned on your finger, which is one of the main reasons for the notch, but not the only one.
Positioning and precision
To get the best results from the biomonitoring feature, you should place the small notch you see on an Oura ring under your finger. This basically tells you where the bottom of the ring is and which side should not be visible from the top of your hand. This is especially important for models like the Oura Ring 4 that have recessed sensors and don’t emit bright, visible LED lights that you can see (and can be quite distracting) while measuring. Conversely, it’s also not as strictly necessary for this new model since it has something called Smart Sensing with more than double the signal paths compared to the Oura Ring 3. This means that even if the ring moves on your finger while you move or sleep, it can still track the data accurately and continuously, reducing discrepancies in measurements caused by ring movement.
No matter which Oura Ring you have, proper positioning is the best way to ensure the most accurate data collection possible. And this notch also serves as a tactile cue. If you wear the ring on your index, middle, or ring finger, the three best fingers to wear a smart ring on for better blood flow measurement, you should be able to reach your thumb and feel the notch. If you can’t feel it on the underside, you can use your thumb to rotate the ring. If it’s too snug to do this, use your other hand to reposition it.
It is also for load alignment
The notch on the Oura Ring is also a handy guide for charging. Otherwise, it can be tedious to figure out how to properly install a smart ring on the charging dock or in the case. This notch shows you how to align the ring immediately. With the Oura Ring 4, you’ll notice a corresponding notch on the charging dock that indicates how to place the ring. Simply line up the notch on the ring with the notch on the dock. Interestingly, the new charging case, which works with the Oura Ring 4 and Oura Ring 4 Ceramic, doesn’t have a notch. But the notch still helps with alignment – ​​remember you need to position it on the front of the magazine.
The notch is particularly useful for the Oura Ring 4 since the sensors on the underside are recessed into the case and visible all around, making it difficult to know the correct position for the most precise tracking. With older models like the Oura Ring Gen3 Horizon, it’s important to feel that pill-shaped notch since this smart ring doesn’t have Smart Sensing. The Oura Ring Gen 3 Heritage Edition has a flat top that makes it easy to position, eliminating the need for a notch. Although they can rotate on your finger, a notch like that on some Oura rings helps ensure tracking is just as precise.
