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How the two rings differ at a glance
| What to compare | Oura Ring 4 | Ultrahuman Ring AIR |
|---|---|---|
| Data subscription | Oura Membership is needed for the full feature set. In the United States, Oura lists $5.99 monthly or $69.99 yearly, before applicable taxes; a new member gets one month included. Without membership, the ring and app still work, but insights and data are much more limited. Oura membership details | Ultrahuman describes AIR as having no mandatory data subscription. Ultrahuman Ring AIR |
| Typical battery life (manufacturer claim) | 5–8 days; actual life depends on size, settings, activity, battery age and use. Oura Ring 4 specifications | 4–6 days. Ultrahuman Ring AIR specifications |
| Charging time (manufacturer claim) | Typically 20–80 minutes, depending on charge level. Oura Ring 4 specifications | 180 minutes for a full charge from 0%. Ultrahuman Ring AIR specifications |
| Sizes listed by manufacturer | 4–15. Oura says its sizing is generation-specific. Oura Ring 4 support | 5–14. Ultrahuman recommends using its sizing kit and says AIR sizing can differ slightly from standard US sizes. Ultrahuman sizing and specifications |
| Published weight | Not stated in the cited Ring 4 support specifications. | 2.4–3.6 g, depending on size. Ultrahuman Ring AIR specifications |
The battery figures are manufacturer estimates, not guaranteed results. In its own comparison, Tom’s Guide reported about six days with Ring 4 and around four days with AIR; those are that publication’s test observations, not a promise of what every wearer will get. Tom’s Guide comparison
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What does each ring cost over time?
Oura’s recurring membership fee
For US customers, Oura lists membership at $5.99 per month or $69.99 per year, before applicable taxes, and includes one month for new members. These are US terms on Oura’s membership page, updated October 6, 2026; fees vary by region. Oura membership terms
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Oura announced Ring 4 at a starting price of $349 in October 2024. That is its launch price, not confirmation of a current offer. Oura’s Ring 4 announcement
#1 Best Overall
- THE WORLD’S SMALLEST SMART RING - 40% smaller than the previous generation, Oura Ring 5 is thinner, lighter and smaller than ever. The updated all-titanium design is more scratch-resistant and comfortable than ever
- SIZING IS ESSENTIAL - Oura Ring 5 uses unique sizing different from standard jewelry rings and other Oura Ring generations; use the Oura Ring 5 Sizing Kit to find your perfect fit before purchasing
- EVERYDAY HEALTH SENSING - Oura tracks over 50 health metrics, including sleep, activity, stress, heart health, metabolic health and women’s health metrics. Oura seamlessly integrates with over 40 apps including Natural Cycles, Strava, & more
- OURA MEMBERSHIP - First month of membership is included with purchase, for new members only. Subscription is 5.99/mo afterwards. Membership is tied to your account via the Oura App, not your physical ring
- REBUILT FOR GREATER ACCURACY - Oura Ring 5 has been re-engineered and reconfigured, providing more precise personal health data. Larger, smarter sensors bring research-grade accuracy—all in Oura’s smallest form factor yet
Ultrahuman’s subscription approach
Ultrahuman’s product page presents Ring AIR without a mandatory data subscription. That distinction can make the ownership-cost calculation simpler if you want ongoing access to ring data without adding a required recurring fee. Product prices and availability can change by region and over time, so check the local product page before buying. Ultrahuman Ring AIR product page
Tom’s Guide reported a $349 price for AIR in its comparison, but that report should not be treated as a current regional price. Tom’s Guide comparison
For a fair cost comparison, add the ring’s current local purchase price to any subscription fees you expect to pay over your intended ownership period. Don’t use an old review price as a guarantee of what either ring costs today.
What do the rings track, and how do their apps feel?
Oura Ring 4: broad features with full access tied to membership
Oura lists detailed sleep analysis, 24/7 heart rate, temperature monitoring, blood oxygen sensing, daytime stress, activity, heart health, metabolic health and women’s health features among the membership offerings. The full feature set requires membership; without it, the ring and app remain usable but provide much more limited data and insights. Oura membership features
Rank #2
- 【Check the Size Before Purchase】 Before buying the prxxhri Smart Ring, we strongly suggest that you refer to the size chart and carefully measure the circumference of your finger. This will ensure you get the most comfortable wearing experience and easily avoid any unnecessary returns or exchanges.
- 【Real-time Accurate Sleep & Fitness Monitoring】 prxxhri smart ring tracks your sleep quality and daily activities in real time. With advanced sensors, it provides precise data about your sleep cycle, helping you optimize rest and recovery. Whether you are tracking steps, calories or exercise performance, this smart ring can provide you with the most accurate insights to support your fitness goals and enhance your overall health.It is a good choice for family and friends.
- 【Health Monitoring】The prxxhri ring features advanced 4.0 sensors that automatically measure your heart rate every 30 min when worn. It provides continuous health tracking and comprehensive wellness management all day.
- 【2-3 Day Battery Life】 With a 2-3 day battery life, the prxxhri smart ring ensures continuous health monitoring without frequent charging. When used with the smart charging case, the usage time can even exceed 5 days. Whether you are tracking sleep patterns or fitness activities, you can count on long-lasting performance without constant interruptions.
- 【80-meter Waterproof, Suitable for Various Scenarios】 The prxxhri Smart Ring has excellent waterproof performance, with a waterproof depth of up to 80 meters. Whether it's for daily wear, an intense workout session or a pleasant swimming time, it can handle it with ease. What's more, even if you have sensitive skin, you can still enjoy an extremely comfortable wearing experience when wearing this ring.
Ring 4’s manufacturer-listed hardware includes red and infrared LEDs for blood oxygen sensing during sleep, green and infrared photoplethysmography (PPG) for heart rate and heart-rate variability, a temperature sensor and an accelerometer. These are sensor specifications, not proof of clinical accuracy. Oura Ring 4 specifications
Ultrahuman Ring AIR: no required data subscription and a more data-rich presentation
Ultrahuman lists PPG, skin-temperature and motion sensors for AIR. The manufacturer also specifies iOS 15 or later and Android 6 or later compatibility. Ultrahuman Ring AIR specifications
In Tom’s Guide’s comparison, the reviewer found Oura’s app easier to scan at a glance and Ultrahuman’s more data-rich. That is one publication’s assessment of the app experience, not a universal preference; consider whether you want quick summaries or more detail surfaced in the app. Tom’s Guide comparison
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Fit, materials and comfort
Use the sizing kit for the ring you intend to buy
Ring sizes are not interchangeable between these products. Oura lists Ring 4 in sizes 4–15 and says each generation has its own sizing. Ultrahuman lists AIR in sizes 5–14, recommends its sizing kit and notes that its sizes may differ slightly from standard US sizes. Try the correct product-specific sizing aid and follow the maker’s fit guidance before ordering the finished ring. Oura sizing guidance; Ultrahuman sizing guidance
Rank #3
- 【Size Before You Buy】Before purchasing the Milavan Smart Ring, we recommend referring to the size chart and carefully measuring your finger circumference. This helps ensure a comfortable fit and avoid unnecessary returns or exchanges
- 【Wellness Tracking】The slim ring features advanced 4.0 sensors that automatically track your heart rate every 30 minutes while worn. Daily data is available in the app for reference only and is not intended for medical use
- 【Intelligent Sleep Tracker】The fitness ring automatically tracks your sleep quality, including deep and light sleep, REM (eye movement), and awake periods. You can view all sleep data anytime in the app for daily reference
- 【8 Sports Modes Tracking】Supports 8 sports modes, including Running, Cycling, Jump Rope, Walking, Hiking, Yoga, Dancing, and Golf. View workout duration, steps, heart rate, speed, calories burned, distance, and other activity data in the app
- 【Stylish Fitness Companion】Featuring a slim 2mm profile and a specially polished inner surface, this smart ring is designed for comfortable all-day wear and most sports activities. View detailed workout data in the app after selecting a sport mode
Construction and size-dependent weight
Oura describes Ring 4 as fully titanium, with recessed sensors, and specifies 100 m water resistance. Ultrahuman lists AIR as having a titanium exterior with a tungsten-carbide-carbon coating and an epoxy inner coating. AIR’s published weight varies by size from 2.4 to 3.6 g; the cited Oura Ring 4 support specifications do not provide a weight, so an exact head-to-head weight difference cannot be stated from those specifications. Oura Ring 4 specifications; Ultrahuman Ring AIR specifications
Comfort is personal and can depend on finger, fit, and daily use. A published weight range alone cannot tell you which ring will feel better on your hand.
Which ring is more accurate?
The cited comparison does not establish a lab-tested or clinical accuracy winner. Tom’s Guide found the rings’ sleep measures broadly similar in its test, but noted differences in sleep-stage transitions; the publication also cautioned that its comparison could not determine which ring was most accurate without lab testing. Treat the rings as wellness-tracking devices, not diagnostic tools, and don’t infer accuracy from a sensor list or feature count. Tom’s Guide comparison
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Which one should you choose?
Choose Oura Ring 4 if
- You want Oura’s listed breadth of sleep, stress, activity, heart-health and women’s-health features.
- You prefer the at-a-glance app experience described by Tom’s Guide.
- You value Oura’s published 5–8-day typical battery range and accept paying for membership to access the full feature set.
- You are specifically looking for Oura’s feature set for women’s health; check current availability and suitability for the features you need.
Choose Ultrahuman Ring AIR if
- Avoiding a mandatory data subscription is a priority.
- You prefer a more data-rich app presentation, as described in Tom’s Guide’s comparison.
- A published weight range of 2.4–3.6 g, depending on size, is useful to your decision and you want to consider a lighter-ring option.
- You are comfortable with its 4–6-day manufacturer battery estimate and its 180-minute full-charge estimate.
Before you order
- Try the correct sizing kit for your chosen model rather than relying on your usual ring size.
- Check local prices, taxes, feature access and availability; prices and membership terms can vary by region and change over time.
- Decide whether you would rather pay a recurring fee for Oura’s full feature set or avoid a required data subscription with AIR.
- Think about which app presentation you are more likely to use consistently: a quick scan or more surfaced detail.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
