Answer first

The IW371759 sits in the IWC Portugieser Chronograph family. That family uses a 41 mm steel case, a two-register chronograph layout, and the IWC Calibre 69355. A replica of this reference copies the case and dial. It does not copy the movement, finishing, or materials at the same level. I could not find a public IWC spec sheet for IW371759 itself. Reference numbers in the IW3716xx series differ by dial color, case metal, and strap. Confirm the exact variant before you compare.

What the original does

  • Case: stainless steel, 41 mm across, 13.1 mm thick on the Portugieser Chronograph 41.
  • Water resistance: 3 bar, about 30 meters. Not a dive rating.
  • Crystal: sapphire, anti-reflective coating on both sides.
  • Movement: IWC Calibre 69355, automatic, 4 Hz (28,800 vph), 46-hour power reserve.
  • Dial: elapsed minutes at 12 o'clock, running seconds at 6, applied numerals, feuille hands.
  • No date window on the Portugieser Chronograph.

Those numbers come from IWC listings for the Portugieser Chronograph 41. Use them as the target a replica is measured against.

What replica listings show

Listings for a replica IW371759 vary more than the reference number suggests.

  • Case diameter: 40 mm to 41.5 mm.
  • Thickness: 12.5 mm to 14.5 mm.
  • Movement: Seagull ST19 hand-wound at 21,600 vph, an Asia 7750 automatic at 28,800 vph with a modified plate, or quartz in the lowest tier.
  • Crystal: sapphire on high tiers, mineral glass on low tiers.
  • Strap: leather, rubber, or a steel bracelet.

A 12 o'clock and 6 o'clock subdial layout does not match the base architecture of the Valjoux 7750, which puts running seconds at 9 o'clock. Builders use a hand-wound chronograph or a reworked automatic. Ask which movement is inside before you pay.

Checks that separate tiers

  1. Measure the case. 41 mm across, 13.1 mm thick.
  2. Check subdial positions. Minutes at 12, seconds at 6.
  3. Press the pushers. Start at 2 o'clock, reset at 4 o'clock. A soft reset points to a low-grade module.
  4. Look at the hands. Feuille shape, clean edges, no paint overspill.
  5. Inspect the crown and caseback engraving. Logo depth is shallow on low tiers.
  6. Weigh the watch. Light cases use plated brass or alloy. Steel cases feel heavier.

Price bands

Replica listings for this reference fall into three bands: about $80 to $150 for quartz and low-grade automatic, $200 to $400 for mid-tier automatic, and $450 to $900 for high-grade replicas with clone movements and sapphire. Genuine steel Portugieser Chronograph models list near $8,000 on iwc.com. Prices change.

Legal position in the US

Replicas of this reference carry the IWC name and logo, so they count as counterfeit goods. Trafficking in counterfeit goods is a federal crime under 18 U.S.C. 2320. CBP can seize shipments at the border and assess civil penalties. The OECD puts counterfeit and pirated goods at about 3.3% of world trade. Watches sit among the most copied categories.

What I cannot confirm

I could not verify a public specification page for the exact reference IW371759, a production year, or limited-edition status. I also cannot confirm movement details for a named replica factory. Sellers change suppliers without changing the listing.