OMEGA cal: 590 - 593
Rare Omega caliber produced only in 1959 for Seamaster watches, total production of 590 and 591 was 60.000 pcs.

Technical data Omega cal: 591
- 20 jewels automatic wind, center second.
- S: = 27.80 mm.
- H: = 5.35 mm.
- N: = 19.800 A/h.
- Power reserve: 48 h.
Versions:
- 590: 17 jewels.
- 591: 20 jewels.
- 592: 17 jewels, date.
- 593: 20 jewels, date.