Short answer

IW371689 sits in the IWC Portugieser Chronograph 41 family. The watch is 41 mm wide, 13.1 mm thick, and runs calibre 69355, an automatic column-wheel chronograph with a 46-hour power reserve. Replica copies of this reference sell in three bands: about $120 to $250 for basic builds, about $300 to $450 for mid-tier builds, and about $500 to $800 for builds that copy the 69355 layout. A reference number printed on a box or card proves nothing. Check the case, the subdials, the movement, and the strap instead.

Genuine spec sheet

  • Case: stainless steel, 41 mm diameter, 13.1 mm thick
  • Lug width: 20 mm
  • Crystal: sapphire, front and case back
  • Water resistance: 30 m, 3 bar
  • Movement: IWC calibre 69355, automatic, column wheel, 46-hour reserve, 28,800 vph
  • Dial: subdials at 12 and 6, date at 3, applied numerals, leaf hands
  • Strap: alligator leather with a pin or folding buckle

Variants in the line share these numbers. Dial color, strap color, and case metal change across references. The case dimensions do not.

Replica tiers

Budget builds use a modified Valjoux 7750 or a low-grade automatic. The subdial spacing shifts, the pushers feel soft, and the rotor is plain. Mid-tier builds add a decorated rotor and sharper dial print. Top builds use a clone of the 69355 with a working column wheel and correct subdial positions.

Ask for four photos before you pay: dial at 12, case back, crown side, and a short video of the chronograph start, stop, and reset.

What to check

  1. Subdials. They sit at 12 and 6, stacked on a vertical line. Off-center subdials mean a wrong base movement.
  2. Hands. The chronograph seconds hand snaps back to zero on reset. A slow return points to a cheap module.
  3. Date. The window sits at 3 and shows one number.
  4. Print. "IWC" and "SCHAFFHAUSEN" read sharp at 10x magnification.
  5. Weight. A steel 41 mm case on a leather strap lands near 85 to 95 grams.

What a replica does not give you

No IWC warranty. No service from an IWC boutique. Parts do not swap with the genuine calibre. Water resistance is not tested to 3 bar. Resale value runs at a fraction of the purchase price. Treat the watch as a lookalike, not an investment.