Omega 861

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  No: 30 581 475, manufactured aprox: 1971
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  From Speedmaster MK II

Data Omega 861 (Base caliber: Lemania 1873).

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  17 jewels, manual wind chronograph.
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  Size: 12''' 27 mm.
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  H: = 6.87 mm.
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  N: = 21600 A/h.
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  Power reserve: 40 h.

Versions:

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  860: 17 jewels, base calibre, same as Lemania 1872.
• 861: 17 jewels, 12 h. counter, same as Lemania 1873.
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  862: 21 jewels, 12 h. counter.
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  863: 21 jewels, 12 h. counter, jubilee edition.
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  864: 21 jewels, 12 h. counter, jubilee chronometer.
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  865: 17 jewels, only 60 s. counter, chronostop.
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  866: 17 jewels, like 860 with date, moon phase.
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  867: 21 jewels, 12 h. counter, jubilee chronometer, skellettonized.
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  910: 17 jewels, 12 h. counter, 2nd time zone, 24 h. display.
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  911: 17 jewels, 12 h. counter, 2nd time zone.
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  920: 17 jewels, only 60 s. counter, date, chronostop.
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  930: 17 jewels, like 860 with date.