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Sinn U50 S L

Reference 1050.0203. A sheet to take with you: the numbers to check the watch against, what to look at, and what to ask. It does not authenticate anything and it does not tell you whether to buy.

Check the numbers

Measure or ask. A watch that does not match these is not necessarily wrong, but it is a question worth the answer.

Anything above marked not recorded is a gap in this catalog, not a property of the watch. Do not read a blank as a zero.

Before anything else

A discontinued limited edition of 500 in German Submarine Steel with a black hard coating. The risk here is not counterfeiting but coating wear and the edition paperwork, and the dial is unusual enough to be worth understanding before viewing.

What to look at

1. case Black hard coating condition
   Correct Even matte black across case and bezel with no bright metal showing at the edges
   Red flag Bare steel at the lug tips or bezel edge, which cannot be locally restored
2. dial Fully lumed hybrid ceramic dial
   Correct The entire dial surface charges and glows, not just the markers
   Red flag Glow confined to applied plots, which would indicate a conventional dial and a different reference
3. movement Caliber SW300-1, no date
   Correct Automatic winding with hacking seconds and hand-winding; hours, minutes and seconds only
   Red flag Any date indication, or a crown position that suggests a date quickset
4. crown Screw-down crown against the 500m rating
   Correct Crown seats fully and smoothly; a 50 bar rating depends entirely on it
   Red flag Rough threads or a crown that does not seat, which should be resolved before the watch goes near water

Known issues on this reference

• The dial is a fully lumed hybrid ceramic surface rather than a printed dial with lume plots. It looks different in daylight from a conventional dial and that is correct, not a fault.
• The U50 S L has no date. A U50 with a date window is a different reference, not a variant of this one.
• The black finish is a hard coating over a TEGIMENT-hardened base rather than a PVD layer on soft steel, so it resists marking well; but where it has been through, it cannot be spot-repaired.

Parts that are commonly replaced

• Straps and bracelets are swapped routinely on the 20mm lug width.
• Crown and caseback gaskets are ordinary service parts and should be replaced at any pressure test.

Ask the seller, whatever the watch

• When was it last serviced, by whom, and is there paperwork?
• Has the case ever been polished?
• Which parts are not original to it?
• Do you have the box, papers and the original bracelet or strap?
• Why are you selling it?
• Can I see it in daylight, and can I take a photo of the caseback?

What this sheet is standing on

The specifications above are sourced to sinn.de, monochrome-watches.com. What else the catalog does not know.

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