Short answer
The IW371785 sits in IWC's Portugieser Chronograph numbering block, the 3717xx range. That family is built around a 41 mm case, a bi-compax dial with the two sub-dials stacked at 12 and 6, an automatic chronograph movement in recent versions, and a choice of leather strap or metal bracelet depending on the variant. The 3717xx block covers several dial and case-metal combinations, so confirm the exact case material, dial color and calibre on IWC's own product archive before you compare any listing, genuine or otherwise.
Why the reference number carries the weight
Two watches that look identical on a screen can differ in case metal, dial finish, movement and production year. Sellers who quote a reference number without a matching photo set, box, paperwork or service record are usually describing a category, not a specific watch. Get the full reference, the case serial and the calibre in writing before any money moves.
What replica listings usually deliver
A counterfeit Portugieser Chronograph typically uses 316L steel rather than the 904L-grade or precious metals of the original, a plated finish that wears through at the lugs and crown, and a generic chronograph module rather than IWC's in-house calibre. Caseback engraving is shallow or misaligned, the date font is wrong, and no authorized service center will touch the watch or supply parts. Resale value is effectively zero, and the water resistance claim on the dial is not backed by tested gaskets.
Legal exposure in the United States
Trafficking in counterfeit goods is a federal crime, and customs officers seize shipments at the border without compensation to the buyer. Civil liability to the trademark owner is separate from any criminal charge. A purchase that feels private is still a recorded transaction with a paper trail through payment processors and shipping carriers.
How to verify a genuine Portugieser Chronograph
- Match the full reference and case serial against IWC's official records or an authorized retailer.
- Inspect the caseback engraving under magnification for depth, spacing and font accuracy.
- Ask for the service history and confirm it with an IWC service center.
- Check that the warranty card, booklet and box carry matching reference and serial data.
- Have a watchmaker open the case and identify the calibre before you pay.
Alternatives that hold value
A pre-owned genuine IWC Portugieser Chronograph, or a legitimate chronograph from another maker at your budget, keeps its resale value, can be serviced, and carries no legal risk. The look is available without the liability.