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The most powerful smart ring ever made, forged in fire and inscribed in the tongue of Mordor. A limited edition of the Circular Ring 3.
Limited Edition
Not the prettiest interpretation of a fitness band. The only ring carrying a medical-grade ECG, haptics, contactless payment and a health engine that reads you every two minutes.
One ring to rule them all, one ring to find them, one ring to bring them all, and in the darkness bind them.
Engraved by laser at 0.06 mm depth into the polished band — the same script that burned in the fire at Bag End.
Move across the band to bring the fire
Gold-tone PVD over a titanium core, mirror polished, then cut with the inscription at 0.06 mm. Built on the Ring 3 Pro chassis — the smallest hardware Circular has ever shipped.
The ring reads seven raw biometrics and derives 142 metrics from them, refreshed every two minutes — the tightest interval in the category. Nothing is held back for this edition, and nothing sits behind a subscription.
Heart & rhythm
The only ring with an ECG
Touch & tap
It answers back
Sueño
The whole night, staged
Energy & activity
What you have to spend
Mind
Stress, and what to do with it
Women’s health
Read from your vitals
The One Ring edition is a Circular Ring 3 Pro. Every capability above ships with it.
Every night it reads your body from the inside — heart rhythm, breath, temperature, movement — and tells you in the morning what the darkness took and what it gave back.
Wake Up
0
How the night landed, scored the moment you stir
Sueño
0
Staged across REM, deep and light, hour by hour
Energía
0
Readiness for the day, before you feel it
Estrés
3.6
Load through the day, and where the peaks fell
Anywhere on the map
Worn day and night
A story you can wear
Sleep, recovery, stress and rhythm, read every two minutes and explained in plain language. Kira, the coach inside the app, turns the numbers into something you can act on before breakfast.
Pair The One Ring and the Circular app changes with it. The interface takes on the edition’s ember and warm metal, your ring renders in the app as the ring you actually own, and the Tengwar runs quietly through the detail views.
Underneath, it is the same engine every Circular wearer gets. Nothing about the theme changes what is measured or how it is scored — it only changes what it feels like to open.
Today’s brief — one paragraph on what your night and your load add up to.
Chronotype zones — when to train, when to work, when to wind down.
Immunity Index — an early word when your body is fighting something.
Fourteen days of learning
Kira spends the first two weeks building your baselines, chronotype and reference values, so a six-hour night is judged against your body and not a textbook average.
Told, not tabulated
Every morning you get sentences, not dashboards. What happened, why it happened, and the one thing worth doing about it today.
Your notes, correlated
Log a late meal, a hard session or a bad mood and the app folds it into the analysis, surfacing the patterns you would never have spotted alone.
95.9%
SpO₂ at night
91.8% during the day. Against an FDA-approved pulse oximeter, across 1,597 measurements. Accuracy means within 0–3% deviation.
99%
Pulso
Measured against ECG across twenty-six subjects aged 18 to 67, at rest and through the day.
~78%
Sleep staging vs PSG
Average agreement with polysomnography in internal testing, from an algorithm trained on more than 800 clinical recordings.
5 min
Data interval
Among the tightest sampling in the category. Most rings and bands report every ten to thirty minutes.
Validation studies for the sleep and ECG algorithms are in progress, with publication expected in the coming months.
Circular Ring 3 Pro, The One Ring Edition
Gold-tone PVD over the Ring 3 Pro titanium shell, mirror polished.
Tengwar inscription cut by laser into the outer band.
Sensors, haptics, NFC, Circles and firmware identical to Ring 3 Pro.
Everything below is live on the ring you would receive. It arrived over the air, and it is the software The One Ring runs on from the moment you open the box.
The sleep algorithm is trained on more than 800 polysomnography recordings, the clinical gold standard for sleep study. In internal testing it reaches around 78% average agreement with PSG on staging — a meaningful step up on the leading wearables. The training data now includes atypical and clinically relevant sleep patterns, which fixes a real problem: nights the old model failed to detect as sleep at all because the shape did not match.
Noise in the ECG signal is significantly reduced, and AFib detection now holds across many more real-world scenarios.
Your ECG report shows the metrics doctors actually use: PR interval, QRS duration, and QT/QTc intervals. Rhythm detection reaches beyond AFib into categorisation like atrial flutter and ventricular tachycardia.
ECG features on Circular Ring are intended to help you monitor your heart rhythm. They are not a substitute for professional medical diagnosis. Availability of specific rhythm detections may vary by country depending on local regulatory clearance. Always consult a physician about any heart-related concern.
Systolic and diastolic values, plus your full history, at no cost and with no mandatory subscription. A paid tier adds trend analysis, report export and target range analysis on top.
You calibrate against a standard blood pressure cuff three times at setup, then once a month afterward to keep readings accurate.
Blood pressure monitoring on Circular Ring is a wellness feature and is not intended to replace a clinical blood pressure measurement. Speak with a doctor before making any health decision based on these readings.
Bluetooth stability is significantly improved across all smartphones. The root causes behind the intermittent disconnection loop are addressed, so the ring stays reliably connected to your phone.
Circular is pushing to be the best holistic health experience on the market. 2026 was a transition year on the software side, laying the foundation for everything above. 2027 is where it comes together, and much more.
Reserving costs the price of a sizing kit and its shipping, and holds a slot in this limited edition for you.
No. It is a gold-tone PVD coating over the titanium shell of the Circular Ring 3 Pro, polished and then laser-inscribed. The engraving is cut into the metal, not printed on it.
Yes, with Circular Pay. The Ring 3 Pro carries contactless NFC payment, so you can tap to pay with your hand. It also has a haptic engine, so alarms, reminders and alerts arrive as a tap on the finger rather than a noise in the room.
Yes. Pairing The One Ring switches the Circular app into a bespoke theme built for the edition, and your ring is rendered in the app as the one you actually own. All Circles (features), the measurements, scores and algorithms underneath are identical to every other Circular.
No. Every core feature is included with the ring, and new features arrive over the air. Some premium parts of the experience need additional payments — the paid blood pressure tier, for instance, adds trend analysis, report export and target range analysis on top of the free readings.
On servers in France. Your data is anonymised, and Circular is GDPR, HIPAA, NIST and CCPA compliant. You can also sync to Apple Health or Health Connect.
This is a limited edition.
The cost for reserving is the cost of a sizing kit and shipping. A slot for this limited edition will be reserved for you.