Omega 300 (R 17.8), Balance staff, DCN: 1555
- DCN no: 1555
- Fits cal: R 17.8, R 17.8 S, 300, 301, 302, 310, 311
- A: 266
- B: 138
- F: 41
- G: 81
- H: 43
Versions:
- R17,8: sub second, rhodium plated bridges, to 1949.
- R17,8AM: sub second, antimagnetic, rhodium plated bridges, to 1949.
- R17,8SCAM: center second, antimagnetic, rhodium plated bridges, to 1949.
- 300: same as 17,8, sub second, rose gold plated bridges, from 1949.
- 301: same as 17,8AM, rose gold plating, from 1949.
- 302: sub second, incabloc.
- 310: same as 17,8SC, from 1949.
- 311: same as 17,8SCAM, from 1949.