Omega Seamaster De Ville 34mm Watch

Q: What are the key specs and size of this Seamaster De Ville?
A: Reference 166.020 is a 1960s dress watch with an approximately 34–34.5 mm case diameter (excluding crown) and 18 mm lug width. This example features a gold‑plated case with a stainless steel back, a silver‑coloured dial with date, and an automatic movement. Please refer to the product information and Measurements on this page for the exact details of this piece.

Q: Which movement does it use, and how do I set the date safely?
A: This reference was commonly fitted with Omega automatic calibres 562 or 565. On calibre 565, the date is advanced by repeatedly pulling the crown to the setting position (quick‑set). Avoid using the quick‑set or changing the date when the time is around 10 pm to 2 am to protect the mechanism. If the watch has calibre 562, advance the date by moving the hands past midnight repeatedly. If you are unsure which calibre is inside, a watchmaker can confirm.

Q: Is it water resistant and can I swim with it?
A: When new, the Seamaster De Ville of this reference was rated to 3 bar/30 m. As a vintage watch, ageing gaskets and prior servicing mean practical water resistance can no longer be assumed. We recommend keeping it dry; do not shower or swim with it. If water resistance is important to you, have a watchmaker pressure‑test the watch after a complete service.

Q: Is the case solid gold?
A: No. As stated, this example has a gold‑plated case with a stainless steel back. It offers the look of gold with a plated finish rather than solid precious metal. To preserve the plating, avoid abrasive polishing and contact with chemicals or hard surfaces.

Q: What crystal does it have, and can scratches be improved?
A: These were typically fitted with a hesalite/acrylic crystal. Light surface marks can often be polished by a professional using dedicated acrylic polishes; deeper gouges may require crystal replacement during service.

Q: What strap size does it take, and can I change it easily?
A: The lug width is 18 mm, so most 18 mm straps will fit. The watch is currently on a brown crocodile‑embossed leather strap. Strap changes are straightforward, but to avoid scratching the lugs we recommend using proper tools or asking a watchmaker to fit your preferred strap.

Q: How is the case opened—does it have a screw‑down back?
A: Many Seamaster De Ville 166.020 watches use a front‑loading (monocoque/unishell) case that is accessed from the dial side by removing the crystal. Opening and resealing should be left to a qualified watchmaker to avoid damage to the case or crystal.

Q: How often should a vintage Omega be serviced?
A: Omega recommends a complete service approximately every 5–8 years, with water‑resistance checks yearly if that function matters to you. For vintage pieces, service needs depend on use and prior maintenance. Unless stated otherwise in the product information, recent service is not guaranteed—please factor routine servicing into ownership.

Q: What does the reference 166.020 indicate, and what is the year of this piece?
A: The 166.020 designation identifies an automatic Seamaster De Ville with a date display from the 1960s, typically housing calibre 562 or 565. This example is listed as circa 1968, consistent with the production era of the reference.

Q: What is included with the watch?
A: Everything included is listed in the product information on this page. If items such as a branded box or original papers are not listed there, they are not included—please contact us if you would like us to confirm the contents.

Q: How does A Retro Tale authenticate this watch?
A: Every item is vetted by our in‑house experts using multi‑point checks of case and movement numbers, dial printing, hands, crown, crystal type, finishing, and period‑correct components. We stand behind the authenticity of all items we sell and are happy to provide further details on request.