
Wellue O2Ring
Score: 70/100
Withings ScanWatch 2
Score: 79/100Rankings

The Withings ScanWatch 2 combines a classic stainless-steel analog look with a discreet OLED screen delivering ECG, SpO₂, temperature and HRV monitoring, all powered by a 30-day battery. Its heavier weight with the band and small display may be drawbacks for some. Suited for health-conscious professionals who desire premium build and medical-grade sensors.

The Wellue O2Ring is a ring-style pulse oximeter that offers continuous 1-second SpO₂ and heart-rate monitoring with vibration alerts and IP24 protection. Its modest 12-16 hour battery and relatively heavy 15 g design limit all-day wear without frequent charging. Best suited for sleep-focused users and clinicians needing detailed overnight data.
| Attribute | ![]() | ![]() |
|---|---|---|
— | 720 hoursbest | |
2 %best | — | |
| ↓ lower better | 15 gbest | 83 g |
2 bpmbest | — | |
— | 0.63 inchesbest | |
— | 14,504 pixelsbest | |
— | 282 ppibest |
Click an attribute name to sort · Green = best, red = worst (relative to this comparison)
| Attribute | ![]() | ![]() |
|---|---|---|
Battery & Power(1) | ||
Battery Life (hours) | 12-16 hours | 720 hours |
Software(2) | ||
Operating System Compatibility | iOS 9+, Android 5+ | iOS 16+, Android 9+ |
Companion App Compatibility | iOS, Android | Withings App |
Build & Design(3) | ||
Weight (g) | 15 g | 83 g |
Case Material | soft silicone | stainless steel |
Water Resistance (IP Rating) | IP24 | 5 ATM |


Products in the top-left offer the best value (high score, low price).

Professional reviewers commend the O2Ring for its high-resolution 1-second data capture, practical USB-rechargeable battery that lasts about two nights, and robust exportable reporting that supports clinical workflows. However, they caution that the 15-gram weight is relatively heavy for a ring-style device and that the modest battery life may necessitate frequent charging for continuous monitoring.
Users consistently praise the O2Ring's comfort thanks to its soft silicone band, the usefulness of vibration alerts that don't disturb sleep, and the detailed app/PC reports that facilitate sharing data with healthcare providers. Recurring concerns focus on the device's weight and the need to recharge it nightly due to its limited battery endurance.

Professional reviewers praise the ScanWatch 2 for its impressive 30-day battery, premium materials and the seamless hybrid design that merges classic watch styling with modern health sensors. They also commend the precise accelerometer and the addition of temperature and HRV tracking. However, they note the 42 mm model's higher band-included weight and the modest 0.63-inch screen as drawbacks, and they flag inconsistencies in spec listings that could confuse buyers.
Everyday users generally enjoy the lightweight feel of the watch without the band, the long battery life and the subtle hybrid look that doesn't scream 'smartwatch.' The most common complaints revolve around the heft when the band is attached and the limited size of the OLED display, with some confusion about the exact glass material used.
“Gadgetoid highlights the 52.6 g (42 mm without band) as "svelte" compared to the original ScanWatch's 83 g.”
