Ultrahuman Ring AIR vs Circular Ring Slim
Ultrahuman Ring AIR ($349) vs Circular Ring Slim ($259) — side-by-side specs, weight, pros and cons to help you pick the right smart ring.
Spec-by-spec
| Spec | Ultrahuman Ring AIR | Circular Ring Slim |
|---|
| Price | $349 | $259 |
| Weight | 3g | 4g |
| Weight | 2.4–3.6g | 3.8g |
| Battery | Up to 6 days | 4–5 days |
| Sensors | PPG, Temp, Accel | PPG, ECG, Temp, SpO2 |
| Sub | None (free forever) | Optional (Kira AI) |
| WR | 100m | 5ATM |
| Material | Titanium | Titanium |
Pros & Cons
Ultrahuman Ring AIR
- No subscription ever
- 2.4g ultralight titanium
- Sleep + HRV + temperature
- 100m water resistant
- Free app with all features
- Smaller sensor array than Oura
- Newer ecosystem
- Sizing kit required
Circular Ring Slim
- ECG detection unique in this price
- No subscription base tier
- Kira AI coaching
- Slim 2mm profile
- 5ATM waterproof
- ECG not FDA-cleared
- Smaller company = support risk
- Kira AI coaching behind paywall
Circular Ring Slim is the better value at $259. If weight matters most, Ultrahuman Ring AIR carries lighter at 3g. Both are part of our curated smart ring index — tap through to check current pricing.