Certina 23.30-770, Mainspring
- CERTINA original mainspring in factory packaging.
- Fits cal: 23-30, 23-36 (19.800 A/h).
Versions:
- 23-20: 18.000 A/h, sub second.
- 23-30: 19.800 A/h, sub second.
- 23-35: 18.000 A/h, center second.
- 23-36: 19.800 A/h, center second.
