Data: Omega cal 661 (15 RA PC AM 24p).
- 24 jewels, automatic wind, hour and minute display.
- Size: 15.40 mm.
- H: = 4.25 mm.
- N: = 19.800 A/h.
- Power reserve: 42 h.
Versions:
- 660: 17 jewels. 19.800 A/h. (1963)
- 661: 24 jewels, 19.800 A/h, modified automatic mechanism. (1963)
- 662: 17 jewels, 21.600 A/h. major modifications. (1975)
- 663: 24 jewels, 21.600 A/h. (1975)
