Manufacturer | Miyota (Citizen) |
Caliber Number | 0S20 (sometimes typed as OS20) |
Type | Quartz |
Replaces Caliber | Unknown, please add in the comments below |
Diameter | 13.50”’ (30.80mm) |
Height | 5.1mm |
Battery Cell Number | SR927W (395/399) |
Battery Life | Approximately 5 years |
Frequency | 32,768Hz |
Quartz Type | Tuning fork type quartz crystal |
Stem | 065-441 (tap 10) |
Hand Sizes | 1.20/.70/.17 (small hands also .26) |
Jewels | 0 |
Functions | Hours, minutes, central chronograph seconds, 60 minute counter, 24 hour hand, date |
Country of Manufacture | Japan |
Known Models |
Bulova chronograph, Philip Stein Extreme Chronograph, TW Steel A1GP Chrono, Invicta Speedway Chronograph Original Version (Too many to list, add yours to the comments below…) |
The Miyota caliber 0S20 is a quartz chronograph watch movement. You might also see other listings incorrectly refer to this movement at OS2O, but is should be zero-S-2-zero not O.
Some of the topics covered in this caliber listing:
Accuracy:
Miyota claims the accuracy of this movement to be +/-20 seconds/month.
Recalibrating the chronograph hand to zero:
It is common for a quartz chronograph hand to be misaligned after a battery change. If your central chronograph second hand (or chronograph minute hand) is not resetting to 12:00 or “zero” position, you can try the following steps:
- Pull the crown to position 2
- Press button A (top button) to advance the chronograph hand forward until it is lined up with 12:00. If you long-press A, the hand will move forward faster.
- Push button B (bottom button) to reset the 60 minute chronograph hand (subdial located at 9:00).
- Push the crown back to position 0
Note: if you push the crown back in to position 0 while the chronograph hand is still advancing forward, then it will stop the chronograph hand and recognize it as zero position. In this case, you will have to start over again.
Replacement prices:
The average replacement price at the time of this post was from $26.95 – $36.95. Try here.
Macro Gallery:
 Video of 0S20 Assembly and Disassembly:
Examples of watches with Miyota caliber 0S20
Additional Resources:
- Official 0S20 instruction manual (pdf)
- Miyota 0S20 tech drawings (pdf)
- Buy a replacement OS20 movement here
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