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Top-tier supplier movement · caliber IWC Cal. 79320: Valjoux 7750 base, IWC-decorated, 28,800bph, 44h PR, 25j; used in Portofino Chrono and Pilot Chrono 3777 · 44h power reserve
Large case: suits wrists 7 in+ (18 cm+)
43 mm case. A bold, statement-size wear. Best suited to larger wrists where the case sits flush.

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Authentication

Perform a magnet test to verify the soft-iron anti-magnetic inner cage; magnets should not affect timekeeping on this reference.

Known issues in the market
  • The soft-iron inner cage is the defining anti-magnetic feature of the Pilot; it cannot be seen externally but must be present.
  • Cal. 79320 is the same IWC-modified Valjoux 7750 base as the Portofino Chrono; verify IWC signing through caseback.
AreaWhat to checkWhat is correctRed flag
caseAnti-magnetic soft-iron inner cageMagnet held near the case does not affect timekeeping; the soft-iron cage shields the movement from magnetic fieldsAny timekeeping deviation when a magnet is brought near the case; missing cage indicated by magnetic susceptibility
casebackIWC-signed Cal. 79320 movementIWC-signed rotor and movement finishing visible through caseback; Cal. 79320 identity confirmedGeneric ETA 7750 without IWC decoration; unsigned rotor
dialPilot chronograph dial with large Arabic numeralsLarge legible Arabic numerals; pilot-style dial with triangle marker at 12; chronograph registers reading correctlyAny dial not consistent with Pilot specifications; missing triangle at 12
Common legitimate replacements
  • Original IWC Pilot strap; factory replacements are standard.
Expert resources: IWC Pilot Chronograph IW377709 product documentation. IWC anti-magnetic construction specifications.

Authentication guide

Last reviewed June 2026

The IW377709 is the top-tier current-generation Pilot Chronograph at 41mm, using Cal. 69385 (an in-house flyback chronograph caliber with 46-hour power reserve). The black dial with white applied numerals and soft iron anti-magnetic cage are the distinguishing Pilot-line signatures.

Known reproduction risks

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HIGH RISK

Replica Pilot Chronographs with standard (non-flyback) chronograph operations

  • The flyback function is the fastest functional test
  • Soft iron cage absent in almost all replicas
  • Pilot-style pushers on replicas often have incorrect proportions or do not have the oversized travel depth of the originals
  • White dial text quality on replicas is frequently inconsistent at magnification

Dial variants by era

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EraDescriptionIdentifiers
2018 to presentBlack dial with large applied white Arabic numerals at 3, 6, and 9. Central flyback chronograph seconds, 12-hour counter at 12, 30-minute counter at 6, small seconds at 9. White hands.
  • Flyback chronograph with counter at 12 (hours) and 6 (minutes)
  • Small seconds integrated at 9 o'clock
  • Black dial with white or cream dial text and applied white numerals
  • Date window at 3 o'clock
  • Pilot-style pushers: large, easy to operate with gloves
  • "PILOT'S WATCH CHRONOGRAPH" at 6 o'clock

Service part flags

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Movement

Original: Cal. 69385 is an IWC in-house flyback caliber with the Pellaton winding system and 46-hour power reserve.

Replacement tells
  • An ETA 7750 in a stated IW377709; the 69385 is in-house and clearly different in architecture
  • Flyback test: a standard cam-operated chronograph that requires two pushes to reset is not Cal. 69385

Case back markings

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2018 to present
  • Solid steel caseback
  • Engraved: IWC SCHAFFHAUSEN with reference IW377709 and serial
  • Soft iron anti-magnetic inner case visible when caseback is opened
  • The anti-magnetic cage is present on all Pilot line references; its absence means either a wrong case or a modified example

Movement tells

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  • Cal. 69385 runs at 28,800 bph. Power reserve indicator is visible on the dial at 9 o'clock position integrated with small seconds; a movement with no power reserve display is a different caliber.
  • The flyback function is the clearest movement verification: hold the lower pusher during a running chronograph and observe the hands snap back to zero and immediately restart.
Sources: IWC Pilot Chronograph product page; WatchUSeek -- IW377709 reference thread.

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