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.