Short answer

A replica IW371741 is a copy of the IWC Portugieser Chronograph. IWC's published catalog places this model in the IW3714xx and IW3716xx reference ranges. IW371741 does not appear in that catalog, so the number works as a seller label. Judge the watch by photos, measurements, and the movement, not by the number in the listing title.

Dimensions to check

  • Case diameter: 40.9 mm on the 3714 generation, 41 mm on the 2020 generation.
  • Thickness: 12.3 mm on the original. Most replicas built on a Valjoux 7750 base measure 14 mm to 15 mm.
  • Lug width: 20 mm. Strap: leather with a steel pin buckle.
  • Crystal: domed sapphire with anti-reflective coating on both faces.
  • Water resistance: the original is rated 3 bar. Replicas ship with no test certificate.

Dial and hands

The dial has applied Arabic numerals at 12 and 6, a railway track minute ring, leaf shaped hands, and a date window at 3. Chronograph minutes sit in the subdial at 12. Running seconds sit in the subdial at 6. On replicas, inspect the weight of the print on the minute ring, the polish on the leaf hands, and the spacing of the numerals. Thin or fuzzy print and flat hands are common faults.

Movements in replicas

IWC used Caliber 79350 in the 3714 generation. That caliber is a modified Valjoux 7750 with a 44 hour power reserve and a beat rate of 28,800 vph. The 2020 generation uses in-house Caliber 69355 with a 46 hour reserve. The 79350 descends from the 7750, so the subdial spacing on a 7750 clone matches the original dial. That is the reason the 7750 is the base for most of these replicas. A Seagull ST19 version is hand wound, so the crown action and the caseback view do not match an automatic original.

Common faults

  • Case height above 13 mm.
  • Date font and date window position off by a millimeter or more.
  • Printed minute ring that is too thin or doubled.
  • Rotor engraving with visible tool marks under a loupe.
  • Caseback engraving that is shallow or filled with paint.
  • Chronograph pushers with a soft or gritty press.
  • Anti-reflective coating that reads blue or purple under office light.

Checks before you buy

  1. Ask for a caliper photo of case diameter and thickness.
  2. Ask for a movement photo with the caseback off.
  3. Ask for a dial photo at 10x with the chronograph running.
  4. Confirm strap width and buckle type.
  5. Ask for the return window and the payment method in writing.

Prices cover a wide band. A 7750 based replica sells for a few hundred dollars. A hand wound version sells for less. No replica carries an IWC warranty, and no seller can supply IWC service papers for a watch IWC did not make.