Why is Fit 21 better than ONAIR?
- Battery capacity220 mAh vs 180 mAh+22%
Why is ONAIR better than Fit 21?
- Thickness12 mm vs 11 mm+9%
Specifications
Side by side
| Design & durability | ||
| Weight | — | 15 g |
| Thickness | 12 mm | 11 mm |
| Height | — | 46 mm |
| Width | — | 23 mm |
| Case material | — | Plastic / polymer |
| Water rating (maker) | 1 m | — |
| Colours | Black | — |
| Display | ||
| Screen size | 1.54″ | — |
| Panel | Farbdisplay | — |
| AMOLED / OLED display | No | No |
| Resolution (width) | 240 px | — |
| Resolution (height) | 240 px | — |
| Battery | ||
| Battery life (smartwatch mode) | — | 25 days |
| Battery capacity | 220 mAh | 180 mAh |
| Battery type | Li-Ion | — |
| Health sensors | ||
| Optical heart rate | Yes | Yes |
| Blood oxygen (SpO2) | — | Yes |
| ECG | Yes | — |
| Skin temperature | — | Yes |
| HRV tracking | — | Yes |
| Sleep tracking | Yes | Yes |
| Sensors | heart rate, accelerometer | heart rate, SpO2, temperature |
| Connectivity | ||
| Bluetooth | 5 | — |
| Platform | ||
| Works with | iOS, Android | — |









