Circular Ring Slim Smart Ring
French smart ring brand. 2.2mm thickness, 2g weight, no subscription, 5-8 day battery, surface temperature + RGB+IR PPG sensors. Niche alternative to Oura.
3.5 / 5
★★★★★ ★★★★★ Recommended with caveats
Strengths
- 2.2mm thickness is the slimmest in the smart-ring category - most comfortable to wear
- No subscription required (differentiator vs Oura's £5.99/month)
- Temperature sensor (rare at this price tier - useful for cycle tracking + recovery)
Watch outs
- Multiple third-party reviews flag unreliable tracking accuracy vs Oura/Ultrahuman
- Exterior scratches easily per published reviews - cosmetic durability is a real issue
- Claimed 5-8 day battery rarely delivered in real-world use (typical 3-5 days)
£225
Typical price - check Amazon UK for live pricing.
- Brand Circular (French company)
- Thickness 2.2 mm (slimmest in category)
- Weight 2 g
- Sensors Infrared + red + green PPG LEDs, surface temperature, 3-axis accelerometer
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By Editorial team1 min read
- Brand
- Circular (French company)
- Thickness
- 2.2 mm (slimmest in category)
- Weight
- 2 g
- Sensors
- Infrared + red + green PPG LEDs, surface temperature, 3-axis accelerometer
- Battery life (claimed)
- 5-8 days
- Battery life (real-world)
- 3-5 days typical in published reviews
- Charging time
- ~45 minutes
- Subscription required
- No
- Water resistance
- 5 ATM (shower OK; not formally swim-rated like Oura/Ultrahuman)
- App ecosystem
- Circular app (iOS + Android)
- UK shipping
- Yes - global shipping from France
- UK warranty support
- Via Circular direct (France-based, slower than UK-based brands)
- Price (UK)
- £225