What the IW prefix means

IW is the prefix IWC Schaffhausen prints in front of every reference number it issues. A full reference runs eight characters: the letters IW plus six digits. The first four digits name the model family. The last two digits name the version, such as case metal, dial color, or strap. IW377714 is a Pilot's Watch Chronograph. IW500705 is a Portugieser Automatic. A listing that stops at IW3777 or IW5007 shows a family code, not a reference.

Reference format by family

  • IW3777xx: Pilot's Watch Chronograph, 43 mm case, caliber 79320.
  • IW3714xx: Portugieser Chronograph, 40.9 mm case, caliber 79350.
  • IW3716xx: Portugieser Chronograph, 41 mm case, caliber 69355.
  • IW5007xx: Portugieser Automatic, 42.3 mm case, caliber 52010.
  • IW3270xx: Pilot's Watch Mark XVIII, 40 mm case, caliber 35111.

How counterfeit listings use IW numbers

Replica sellers copy the prefix. Two patterns show up. First, a short code with no version digits, so the listing cannot be matched to a real watch. Second, a real full reference attached to a watch that does not match it. Check four items: case size, caliber, dial layout, and date position. The Mark XVIII has a date window at 3 o'clock and no day window. Replica chronographs use copies of the ETA 7750, and the subdial spacing differs from caliber 79320.

Serial numbers are engraved on the caseback and on the movement. IWC prints the reference and the serial on the warranty card and the booklet. A replica will show a serial that does not match the papers, or ships with no papers at all.

How to check a reference

IWC publishes the full reference, case material, case size, and caliber for each model it sells. An authorized dealer or an IWC service center can compare a serial number against factory records. IWC does not publish serial number ranges, so the public cannot date a watch from a serial alone. Since 2022, a watch bought from an authorized retailer can be registered in My IWC to extend the international warranty from two years to eight. A watch that fails registration is a warning sign.

Legal status in the US

Trafficking in counterfeit goods is a federal crime under 18 U.S.C. § 2320. A first offense carries up to 10 years in prison and a $2 million fine for an individual, or $5 million for a corporation. Civil claims run under the Lanham Act, 15 U.S.C. § 1114. U.S. Customs and Border Protection can seize and destroy shipments of counterfeit watches. The personal exemption for returning travelers does not cover counterfeit goods. A buyer who orders one has no legal recourse if the package is seized, and no warranty from IWC.