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Top-tier supplier movement · caliber Mido Caliber 80 Si: ETA C07.621 base with silicon hairspring, 21,600bph, 80h PR, 21j; improved anti-magnetic and anti-shock vs standard Caliber 80 · 80h power reserve (3.3 days)
Medium-large: suits wrists 6.5 in+ (16.5 cm+)
40.5 mm case. Wears confidently on average to larger wrists. May overhang on slender builds.

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Authentication

The Si designation on the caseback confirms the silicon-hairspring Cal. 80 Si variant; without it the watch has the standard Cal. 80.

Known issues in the market
  • The Si designation distinguishes the silicon-hairspring variant; both movements are correct for different sub-references but are not interchangeable designations.
  • The Cal. 80 Si provides anti-magnetic properties; confirm the designation matches the reference being sold.
AreaWhat to checkWhat is correctRed flag
casebackSi designationSi text on the caseback confirms silicon hairspring Cal. 80 Si variantNo Si designation; standard Cal. 80 without silicon hairspring
caseScrew-down crownScrew-down crown engages and disengages smoothly; correct for 200m ratingNon-functioning screw-down; crown threads stripped or incorrect crown installed
dialOcean Star 200C dial textOcean Star 200C designation and correct depth rating textIncorrect depth rating text; wrong sub-reference dial
Common legitimate replacements
  • Rubber or textile strap; Mido OEM.
  • Crystal; sapphire standard.
Expert resources: Mido authorized service; Mido Ocean Star 200C product documentation.

Authentication guide

Last reviewed June 2026

The Ocean Star 200C has the crown positioned at 4 o'clock, a Mido design choice that protects the crown during diving. The 4 o'clock crown position is the single most recognizable identifier on the Ocean Star and a quick authentication check.

Known reproduction risks

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MEDIUM

Crown position substitution: a 3 o'clock crown case presented as Ocean Star 200C.

  • Crown at 3 o'clock is immediately wrong for this reference; no variant of the Ocean Star 200C has a 3 o'clock crown

Dial variants by era

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EraDescriptionIdentifiers
2020 to presentDive watch; multiple dial color options; 200m WR; 4 o'clock crown.
  • Crown at 4 o'clock (not 3); this is a factory design feature
  • "MIDO" at 12; "OCEAN STAR" on dial
  • "200M / 660FT" on dial
  • Unidirectional rotating bezel
  • Fish/waves motif on caseback (signature Mido Ocean Star caseback art)
  • Caliber 80 (80-hour power reserve)

Service part flags

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Crown Position

Original: Crown tube is machined into the case at 4 o'clock; it cannot be moved.

Replacement tells
  • A crown at 3 o'clock on a claimed Ocean Star 200C indicates a different case or a case replacement
  • The crown tube should be integral to the case at 4; any gap or misalignment suggests case damage or repair
Caseback Art

Original: Caseback engraved or embossed with fish and wave motif.

Replacement tells
  • A plain or undecorated caseback on a claimed Ocean Star is incorrect

Case back markings

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2020 to present
  • "MIDO" and "OCEAN STAR" on caseback
  • Fish/waves art engraving
  • "200M / 660FT"
  • "CALIBER 80" or caliber reference
  • "SWISS MADE"
  • Serial number

Movement tells

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  • Caliber 80 in the Ocean Star is identical to other Mido Caliber 80 pieces; same power reserve verification applies.
  • Screw-down crown at 4 o'clock requires correct crown/tube sizing; an improperly fitted crown will not seal correctly for dive rating.
Sources: Mido official site.

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