Oura Oura Ring 4 vs Circular Ring Slim
Oura Oura Ring 4 ($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 | Oura Oura Ring 4 | Circular Ring Slim |
|---|
| Price | $349 | $259 |
| Weight | 6g | 4g |
| Form | Ring (sizes 4–15) | — |
| Battery | 8 days | 4–5 days |
| Sensors | HRV, Temp, SpO2, HR | PPG, ECG, Temp, SpO2 |
| Subscription | $5.99/mo | — |
| WR | 100m | 5ATM |
| Weight | 4–6g | 3.8g |
| Material | — | Titanium |
| Sub | — | Optional (Kira AI) |
Pros & Cons
Oura Oura Ring 4
- Most discreet health tracker
- 8-day battery
- Excellent HRV + sleep data
- No wrist bulk
- Works alongside any watch
- Subscription required $5.99/mo
- No display
- Ring sizing requires order kit
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. Both are part of our curated smart ring index — tap through to check current pricing.