| Manufacturer | Miyota (Citizen) |
| Caliber Number | 0S21 aka OS21 |
| Type | Quartz |
| Replaces Caliber | Citizen 0510 |
| Diameter | 13.50”’ (30.80mm) |
| Height |
5.10mm |
| Battery Cell Number | SR927W |
| Frequency | 32,768Hz |
| Quartz Type | Tuning fork type quartz crystal |
| Stem | 065-453 |
| Hand Sizes | 120/80/18 |
| Jewels | 0 |
| Functions | Hours, minutes, central chronograph seconds, 60 minute counter, 24 hour hand, date |
| Country of Manufacture | Japan |
| Known Models |
REC, Philip Stein Active Chronograph |
The Miyota caliber OS21 is a quartz watch movement with zero jewels. It is made in Japan.
Accuracy Rating
Miyota states the accuracy of this movement to be +/-20 seconds/month.
Additional Resources:
- Official instruction manual (pdf)
- Movement specs from Miyota
- Buy a replacement OS21 movement here
network of watch sites
