- IWC original balance staff, not in factory packaging.
- 1 pcs.
- Fits cal: 853, 8531, C8531
Versions: 13''' (1958 - 1963).
- 853: center second.
- 8531: center second, date, H=6,40 mm.
Versions: 12,5''' (1963 - 1974).
- 854: 21-25 jewels, center second, H=4,85 mm.
- 854B: 23-25 jewels, stop mechanism, H=4,85 mm.
- 8541: 21-25 jewels, date, stop mechanism, H=5,90 mm.
- 8541B: 23-25 jewels, date, stop mechanism, H=5,90 mm.