IWC 8531

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  Serial no: 1 517 165, (aprox: 1962).

Data: 8531

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  21 jewels, automatic winding, date.
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  Size: 13''' 29,0 mm.
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  H: = 6,40 mm.
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  N: = 19800.
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  Power reserve: 44 h.

Versions: 13''' (1952 - 1964).

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  85: center second.
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  851: center second.
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  852: center second (1952 - 1958).
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  8521: center second (1953 - 1958).
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  853: center second (1958 - 1963).
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  8531: center second, date, H=6.40 mm (1959 - 1964).

Versions: 12,5''' (1964 - 1996).

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  854: 21-25 jewels, center second, H=4.85 mm (1964 - 1976).
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  854B: 23-25 jewels, stop mechanism, H=4.85 mm (?).
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  8541: 21-25 jewels, date, stop mechanism, H=5.90 mm (1964 - 1976).
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  8541B: 23-25 jewels, date, stop mechanism, H=5.90 mm (1976 - 1996).