Short answer
No IWC catalogue entry uses the reference IW93811. IWC numbers take the form IW plus six digits, such as IW371617 or IW500705. A five-digit string leaves a gap. Ask the seller for the full number before you send money.
What the number should look like
IWC stamps the reference on the caseback and prints it on the warranty card. The same digits appear in the brand catalogue, in auction archives, and in dealer stock lists. Six digits let a buyer match case diameter, movement caliber, and production window. Five digits match nothing.
Labels sellers use
- Truncated reference: one digit dropped from a six-digit number.
- Factory code: a workshop tag with no link to the original model.
- Batch number: a seller stock label, reused across several models.
Checks before payment
- Ask for a photo of the caseback. Read the digits.
- Search the full number on the brand site. No result means stop.
- Compare case diameter and lug width with the catalogue figure. A 2 mm gap points to a different case.
- Ask for the movement caliber. Sellers often write "Swiss" with no caliber number.
- Request the serial and the reference in one photo. Two photos hide a swap.
Legal position in the US
US Customs can seize and destroy counterfeit watches at import. 18 U.S.C. 2320 covers trafficking in counterfeit goods. A buyer who imports a replica risks seizure with no refund. The seller keeps the money.
Bottom line
IW93811 matches no IWC model I can verify. Treat a listing with that number as unconfirmed. Get the six-digit reference first, then decide.