IW371789 is an IWC reference number. IWC formats references as IW plus six digits. The 3717 block sits in the Portugieser chronograph family. IWC does not publish a page for the exact 789 suffix that I can confirm, so any listing that carries this number needs a caseback check before you trust it.
Genuine specs to compare against
- Case: stainless steel, 41 mm across, about 13 mm thick
- Crystal: domed sapphire with anti-reflective coating on both faces
- Movement: IWC caliber 69355, automatic, column wheel chronograph
- Rate: 28,800 vph (4 Hz)
- Power reserve: 46 hours
- Water resistance: 3 bar (30 m)
- Dial: two counters, 30-minute totalizer at 12 and small seconds at 6
- Strap: alligator leather, steel pin buckle
Date placement and dial finish change between Portugieser generations. Match the dial to the reference before you compare anything else.
Where replica versions break down
No maker sells a clone of the 69355. Replica cases of 3717-style watches use a 7750 base with a transfer module, or a quartz movement. That shows up in three places.
- Thickness. The module adds height. Copies measure 14 mm to 16 mm against 13 mm for the genuine case.
- Subdial position. The 12 and 6 layout needs extra gearing. On low-grade copies the counters drift off center or the hands run short.
- Caseback. Genuine engraving is deep and sharp. Copies use laser marking with shallow, rounded edges.
Other points to check: crown size, pusher feel, date font, sapphire coating tint, and end link fit on the leather strap.
Price
Steel Portugieser chronographs trade on the secondary market in the low to mid four figures in US dollars. Box and papers move the number. Reported replica prices run from a few hundred to about one thousand dollars. I cannot verify those figures.
Before you buy
- Ask for a caseback photo with the reference engraving and serial clear.
- Ask for a photo of the movement through the display back.
- Run the chronograph for one hour. A 7750-based copy drifts against the main timekeeping.
- Weigh the watch. Steel replicas of this reference run 15 to 30 grams below the genuine weight.
Legal position in the US
Trafficking in counterfeit goods is a federal crime under 18 U.S.C. 2320. US Customs and Border Protection seizes counterfeit watches at import. The OECD and EUIPO put counterfeit and pirated goods at about 3 percent of world trade.