Omega 23.4 (220), Main spring, no: 770

• Manufacturer: Prima, no: 140 K 31

• Fits cal: 23.4, 23.4SC, 24.4SCT1, 23.4T2, 220, 230, 231

• H: 1,40
• D: 9
• F: 0,095
• L: 310

Versions:

• 220: (23.4 until 1949), sub second.
• 230: (23.4SC until 1949), center second.
• 231: (23.4SCAM until 1949), center second, antimagnetic.