In early 2025, Circular introduced its second-generation smart ring—Circular Ring 2—revealed post-CES and promising to elevate smart ring technology with advanced health features, premium build quality, and a seamless user experience. Priced at around $380, it positions itself as a subscription-free alternative to offerings like the Oura Ring 4 and the upcoming Samsung Galaxy Ring.
Design and Build
The Circular Ring 2 features a titanium casing available in gold, silver, rose gold, and black. The switch to a full titanium exterior gives it a sleek, scratch-resistant, and lightweight finish (weighing about 2 grams), a step up from the earlier mix of plastic materials.
The comfort factor is notable—lightweight, smooth, and durable. It is water-resistant with an IP68 rating, making it suitable for showers and workouts, though not recommended for swimming.
Health Features and FDA-Cleared AFib Detection
What truly sets the Ring 2 apart is its FDA-cleared atrial fibrillation (AFib) detection, enabled by an on-finger ECG sensor array and PPG technology. This makes it the first smart ring to offer hospital-grade AFib detection without needing an external accessory.
The device captures ECG data in about 30 seconds and is also capable of detecting conditions such as tachycardia and bradycardia.
It integrates with Circular’s AI-powered health assistant, Kira, which tracks over 140 health and wellness biomarkers including heart rate, heart rate variability, SpO₂, body temperature, sleep stages, and stress levels. All insights are available with no monthly subscription fee.
Battery Life and Charging
The battery offers up to 8 days of life in Eco mode (limited sensor use) and around 4 days in performance mode (full tracking enabled).
The updated charging dock is now more stable and intuitive, eliminating the fidgety setup of earlier models.
Digital Sizing and App Experience
Circular’s digital sizing tool is a standout feature. Users can determine their ring size using a smartphone camera and a credit card-sized item—no more waiting for physical sizing kits.
The companion app has also received a significant overhaul. It now features smoother navigation, faster syncing, and a dramatically reduced calibration period of about 4 days compared to the original Ring’s 14-day setup.
Pros and Cons
Pros:
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Titanium build offers premium feel and durability
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FDA-cleared AFib detection provides medical-grade value
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Subscription-free access to all features
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Accurate digital sizing eliminates waste and waiting
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Long battery life and improved charging dock
Cons:
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AFib/ECG accuracy still undergoing real-world validation
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Eco mode limits full tracking capabilities
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No haptic motor or silent alarm (removed to fit additional sensors)
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App data accuracy will need to be tested in the wild
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Competing offerings from bigger brands like Samsung could challenge its market position
Verdict
Circular Ring 2 represents a significant leap forward from its predecessor. With FDA-cleared ECG capabilities, a polished titanium build, and no recurring fees, it stands as one of the most compelling smart rings available in 2025. If its medical claims and app performance hold up in daily use, this device could set a new standard for smart health wearables.
Expected retail price: Approximately $380.
