Short answer
IW371640 is an IWC Portugieser Chronograph reference. Watches sold as a "replica IW371640" are unlicensed copies. They have no IWC warranty, no factory service path, and little resale value, and counterfeit watches can be seized at import. This guide does not help you choose a copy or a seller. It explains what the copies are, what they cost you, and how to confirm a genuine watch before money changes hands.
What the reference covers
The Portugieser Chronograph is a stainless steel chronograph with a clean dial, two counters, and an IWC-made movement. Each reference number locks in a specific case, dial, and movement combination, so two watches from the same family can differ in dial color, hands, and finishing. A copy often matches the look of one part and misses the rest. Confirm the full reference string, the case serial number, and the movement number as a set.
Risks of buying a copy of this reference
Legal exposure
In the United States, trafficking in counterfeit goods is a federal offense under 18 U.S.C. 2320, and Customs and Border Protection can seize counterfeit shipments at the border. A purchase order does not remove that risk from the transaction.
No service path
IWC service centers decline counterfeit watches. Independent watchmakers often refuse the work as well, because the movement inside a copy is a generic or cloned calibre that shares no parts with the real item. When it stops, you own a paperweight.
No resale market
A copy sells for a few hundred dollars and resells for less. It cannot be listed honestly as an IWC, and any buyer who learns the truth can pursue a refund or a claim.
Fraud in both directions
Sellers of copies misrepresent grade, shipping, and materials with no recourse for the buyer. Buyers who pass a copy off as genuine take on civil and criminal liability.
How to verify a genuine IW371640
- Ask the seller for the full reference number, case serial number, and movement number in writing.
- Request clear photos of the caseback engraving, the dial, the crown, and the pushers.
- Send those numbers to an IWC authorized dealer or IWC service center and ask for confirmation.
- Inspect the dial printing under magnification for font weight, spacing, and subdial alignment.
- Check that the date sits square in its window and that the chronograph resets to zero.
- Have a qualified watchmaker open the caseback and confirm the movement matches the reference.
- Complete the inspection before you pay, not after.
If you already own one and are unsure
- Stop wearing or listing the watch until you know what it is.
- Take it to an IWC authorized service center for a written assessment.
- Compare the result against the paperwork you received at purchase.
- If it is counterfeit, contact the seller and your payment provider to dispute the sale.
Where to buy an authentic IW371640
Authorized IWC dealers and IWC boutiques sell authentic pieces with full provenance. On the pre-owned side, buy from sellers who provide service records, original boxes and papers, and a return window long enough for an independent inspection. Expect to pay market price for a real watch. Any offer far below the going rate for a Portugieser Chronograph is a signal to walk away.