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Omega Speedmaster Professional Chronograph 'Pre-Moon' Calibre 861 Circa 1969 – Carter Marsh: Pre-owned Luxury Wristwatches
OMEGA Speedmaster: The Evolution of Calibers 321 and 861, by Bernhard Stoeber — Horological Society of New York
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Omega Speedmaster Chronograph Professional Caliber 861 42mm Hesalite Vintage Year 1976 Speedy 145022-76 ST | Sansom Watches, Rolex, Breitling, Omega, and more
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