Windows Errors? Fix Them Before They Spread
Repair common Windows errors and clear accumulated junk for a smoother, more stable PC - no reinstall needed.Free scan · no reinstallCrashes, No Sound, or Screen Glitches?
Random freezes, missing sound and display glitches usually trace back to one bad driver. Find and replace yours safely.Free scan · under a minuteCircular announced the Ring 2 at CES 2025 as a titanium smart ring with a single-lead ECG, AFib-related rhythm detection, redesigned software, and up to eight days of battery life. The company initially said it would launch in February or March 2025 for about $380. Circular’s later product page listed the ring at $349, but its FDA language requires an important qualification: the available FDA records clearly cover B-Secur’s HeartKey ECG-analysis software, not an independently confirmed final-device clearance record for the complete Circular Ring 2.
What Circular announced at CES 2025
Circular unveiled the Ring 2 at CES 2025 Unveiled in Las Vegas on January 5, 2025. The announcement positioned it as a major revision of the company’s smart ring, combining sleep and wellness tracking with an on-demand electrical heart-rhythm check.
As an Amazon Associate I earn from qualifying purchases.
The headline features were a single-lead ECG, AFib detection, a redesigned companion app, digital ring sizing, and an advertised battery life of up to eight days. Circular announced four finishes—gold, silver, black, and rose gold—and said the ring would launch initially in the United States, United Kingdom, France, and other markets. TechCrunch’s CES report recorded the original approximately $380 price and February-or-March launch window.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
That announcement was not the same thing as immediate, broad retail availability. The Ring 2 began as a Kickstarter project and rolled out over time. Availability, stock, delivery timing, and return terms can therefore differ by country and should be checked directly before ordering.
#1 Best Overall
- 【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
How the Ring 2’s ECG works
Circular’s later product information describes a 40-second, on-demand ECG check whose result appears in the app and can be exported as a PDF. The CES announcement described the hardware as a single-lead ECG.
An ECG measures the heart’s electrical activity. That is different from the optical PPG sensors commonly used for continuous heart-rate and blood-oxygen estimates. A single-lead recording can provide a useful rhythm snapshot—particularly during symptoms or a scheduled check—but it is not equivalent to a 12-lead clinical ECG and cannot evaluate every cardiac condition.
Readings may be inconclusive or unreadable. Movement, moisture, sweat, a loose or incorrectly oriented ring, poor skin contact, and electrical noise can all affect the result. An inconclusive reading is not itself a diagnosis, and a normal reading does not rule out a health problem.
What AFib detection means—and what it does not
Atrial fibrillation, or AFib, is an irregular heart rhythm associated with an increased risk of stroke. The Ring 2 is designed to flag rhythm patterns suggestive of AFib; it should not be treated as a device that independently diagnoses AFib or rules it out.
Circular describes the feature as using validated, FDA-cleared technology. The FDA materials for B-Secur’s HeartKey software identify possible outputs including normal sinus rhythm, atrial fibrillation, bradycardia, tachycardia, inconclusive, and unreadable results. In practical terms, an alert is a reason to seek professional evaluation—not a diagnosis or treatment plan.
Rank #2
- 【Check the Size Before Purchase】 Before buying the BIEMHA 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】 BIEMHA 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 BIEMHA 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 BIEMHA 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 BIEMHA 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.
Important medical limitation
No alert does not prove that AFib is absent. Do not use the Ring 2 to make medication decisions, replace a prescribed monitor, or manage a known arrhythmia without medical guidance. Anyone experiencing chest pain, fainting, severe shortness of breath, or possible stroke symptoms should seek urgent medical care rather than relying on a ring reading.
Is the Circular Ring 2 FDA-cleared?
The most accurate answer is narrower than the marketing shorthand.
The FDA database shows that B-Secur’s HeartKey Software Library received 510(k) clearance under K200884. B-Secur’s HeartKey Rhythm also received a separate 510(k) decision under K233755. Those records concern ECG signal processing and rhythm-analysis software.
The available records do not clearly establish a final, device-specific FDA 510(k) clearance record for the complete Circular Ring 2, nor do they establish the precise US intended-use labeling or Ring 2 performance statistics such as sensitivity, specificity, or positive predictive value. The HeartKey clearance documentation also makes clear that the manufacturer integrating the software remains responsible for obtaining authorization for the finished device.
Accordingly, the defensible wording is: Circular says its AFib-detection technology is FDA-cleared, and the Ring 2 uses B-Secur technology with FDA-cleared records. It would be inaccurate to simply state that “the FDA approved the Circular Ring 2.” The FDA’s consumer guidance explains the difference between registered, cleared, and approved devices.
Rank #3
- 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
Specifications and advertised features
| Feature | Circular Ring 2 |
|---|---|
| Observed official price | $349 USD on Circular’s product page; prices and promotions can change |
| Body | Titanium with a hypoallergenic interior |
| Dimensions | Approximately 2.55 mm thick and 7.8 mm wide; figures may vary by size |
| Weight | Approximately 3 grams |
| Sensors | Single-lead ECG, PPG, temperature sensor, and three accelerometers |
| Connectivity | Bluetooth Low Energy; iOS and Android compatibility advertised by Circular |
| Charging | Wireless charging case and USB-C cable; approximately 30 minutes claimed for recharging |
| Battery | Up to eight days in Power Mode or up to five days in Performance Mode |
| Sizes | US sizes 6 through 14, with no half sizes listed |
| Finishes | Gold, silver, black, and rose gold |
The eight-day number is a manufacturer maximum, not a guaranteed everyday result. Frequent ECG checks, workout sessions, continuous sensing, Bluetooth synchronization, firmware, ring size, and temperature can reduce endurance. Circular’s current product page distinguishes Power Mode from the more demanding Performance Mode, where it lists up to five days.
Advertised wellness features include heart rate and HRV, sleep stages, breathing rate, blood oxygenation during rest and sleep, skin-temperature trends, activity and sport sessions, stress tracking, energy scoring, women’s-health tracking, guided breathing, medication reminders, and AI coaching through Kira. These are company-advertised capabilities, not evidence that every measurement is clinically validated for diagnosis.
Sizing and subscription terms
Circular lists US sizes 6–14 and no half sizes. It also promotes digital sizing and a physical sizing kit. Because smart rings generally cannot be resized, fit is more important than finish: the ring should remain secure while allowing comfortable wear as fingers swell or contract during the day. Check exchange and return rules before purchasing, especially when ordering a sizing kit or buying internationally.
The Ring 2 is not simply “subscription-free” in every sense. Circular says core features—including ECG, sleep tracking, energy analysis, activity tracking, HRV, temperature trends, SpO2, stress tracking, women’s-health tracking, and wellness recommendations—are included without a recurring subscription. Its product information also describes a freemium model in which some advanced or future capabilities, including blood-pressure and glucose-trend features, may require payment or Circular Coins. Those capabilities should not be treated as currently available medical functions.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What changed after the CES announcement?
The CES-era approximately $380 price and February-or-March launch window are historical announcement details. Circular’s later official product page listed the Ring 2 at $349 and provided more specific information about sizes, sensors, charging, battery modes, and the subscription model.
Recommended Free Tools
Rank #4
- 【Check the Size Before Purchase】 Before buying the BIEMHA 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】 BIEMHA 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 BIEMHA 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 BIEMHA 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 BIEMHA 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.
That distinction matters when evaluating launch coverage. A product shown at CES may still be in preorder, crowdfunding fulfillment, regional rollout, or software development. Later hands-on coverage reported app bugs, data-transfer problems, missing features, and weak fitness tracking. TechRadar also reported that the ring lacked automatic workout detection compared with some rivals, while Tom’s Guide described manually initiated sport sessions and software limitations.
How it compares with other smart rings
| Ring | Best fit | Main trade-off |
|---|---|---|
| Circular Ring 2 | Buyers who specifically want an ECG spot check and AFib-related rhythm flagging without a mandatory subscription for core features | Smaller-company rollout and software reliability concerns; medical-device claims need careful interpretation |
| Oura Ring 4 | Users prioritizing established sleep, recovery, readiness, and health-insight software | Full experience requires an ongoing membership; it is not the direct choice for the Ring 2’s ECG headline feature |
| Samsung Galaxy Ring | People already invested in Samsung Galaxy phones, watches, and Samsung Health | Some health features depend on compatible devices, apps, age, geography, and market; Samsung’s ECG and irregular-rhythm features are primarily documented through compatible Galaxy devices rather than as an equivalent on-ring ECG |
| RingConn Gen 2 | Buyers seeking a lower-cost, subscription-free ring focused on general health, sleep, and battery life | Does not share Circular’s ECG/AFib headline capability in the cited comparisons |
| Amazfit Helio Ring | Budget-conscious users focused on recovery and sleep tracking | Fewer cardiac-monitoring features and narrower sizing and finish choices in comparative coverage |
The practical decision is straightforward: choose Circular because ECG and possible AFib flagging are central to your purchase. Choose Oura if mature sleep and recovery software matter more than cardiac spot checks. Choose Samsung if Galaxy integration is the priority. Consider RingConn or Amazfit when price, battery life, and subscription-free basics outweigh ECG.
Samsung’s health features also have device and market limitations, so buyers should check compatibility on the company’s health-information page rather than assuming every function works on every phone.
Who should buy the Ring 2?
The Ring 2 is most compelling for an iPhone or Android user who wants a discreet wearable with a genuine electrical rhythm spot-check feature, is interested in AFib-related alerts, and does not want a recurring subscription for core sleep and wellness tracking.
It is a weaker choice for someone who needs highly polished workout tracking, automatic exercise detection, a long-established app ecosystem, or clinically supervised monitoring. Software quality is not a secondary detail with a smart ring: synchronization, interpretation, notifications, and data export determine whether the sensors are useful in daily life.
For medical monitoring, choose with a clinician rather than by comparing consumer-ring specifications. The Ring 2 can be a wellness accessory and may provide a useful rhythm recording, but it should not replace an appropriate medical monitor or professional evaluation.
Quick Recap
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.
