Oura Ring 4 Smart Ring – Size 12
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- Brand new and genuine
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- Titanium smart ring, 7.9 mm wide and about 2.88 mm thick
- Tracks heart rate, HRV, blood oxygen, temperature trends and movement
- Battery typically lasts 5 to 8 days; charges in about 20 to 80 minutes
- Water resistant to 100 m (not for diving)
- Works with iOS and Android; Oura Membership needed for full features
About the Oura Ring 4 Smart Ring – Size 12
Oura Ring 4 is a smart ring that tracks sleep, activity and overall health from your finger, with no screen to manage. It is made from titanium, measures 7.9 mm wide and about 2.88 mm thick, and this listing is for size 12. Oura sizes are chosen with its sizing kit and half sizes are not offered, so it is worth confirming your fit first.
Sensors inside the band do the work around the clock: red and infrared LEDs measure blood oxygen while you sleep, green and infrared sensors track heart rate along with heart rate variability and respiration, a temperature sensor follows body temperature trends, and an accelerometer logs movement. Data syncs over Bluetooth Low Energy to the Oura app on iPhone or Android.
It suits people who want detailed sleep and recovery insights but find a smartwatch bulky to wear in bed. Battery life is typically 5 to 8 days, and charging usually takes 20 to 80 minutes. The ring is water resistant to 100 m, fine for swimming but not for diving. An Oura Membership is required for full functionality.
What reviewers say
Reviewers widely regard the Oura Ring 4 as a leading smart ring, praising its comfortable all-titanium design, detailed sleep and recovery data, and multi-day battery life. The most common complaint is the ongoing membership needed to unlock most features, and several testers found step counts less reliable than a dedicated fitness tracker.
Pros
- Comfortable, low-profile titanium design that is easy to sleep in
- Detailed sleep, recovery and readiness insights in a clean app
- Multi-day battery life, around six days in TechRadar's testing with workouts
- Wide range of sizes and finishes
Cons
- Paid monthly membership required for most features
- Exterior can pick up scratches with daily wear
- Step counts can be inconsistent, and it is a small upgrade for Gen3 owners
Our summary of professional and shopper reviews published elsewhere (Tom's Guide, TechRadar, Wareable, Digital Trends, Engadget and NextPit), as of Oct 9, 2026. These are not reviews of ShopNow4.
Key specs
| Brand | Oura |
|---|---|
| Ring size | 12 |
| Material | Titanium (PVD or DLC-coated exterior, depending on finish) |
| Width | 7.9 mm |
| Thickness | Approx. 2.88 mm |
| Weight | 3.3–5.2 g (varies by size) |
| Battery life | Typically 5–8 days |
| Charging time | Typically 20–80 minutes |
| Water resistance | Up to 100 m (328 ft); not for diving |
| Sensors | Red and infrared LEDs, green and infrared PPG, digital temperature sensor, accelerometer |
| Connectivity | Bluetooth Low Energy |
| Compatibility | iOS and Android |
| In the box | Oura Ring 4, size-specific charger, USB-C cable |
| Membership | Oura Membership required for full functionality |
| Category | Wearables |
| Price | $383.99 |
| Availability | In stock |
| SKU | oura-ring-gen-4-smart-activity-tracker-s-bd25ce |
