The IW371743 is an IWC Portugieser Chronograph reference. A replica of it copies a 40.9 mm steel case, a two subdial layout, and a Valjoux based chronograph movement. Quality varies by factory. Check four points before you pay: case diameter and thickness, subdial spacing, dial print, and the movement inside.
What the reference is
IWC lists the Portugieser Chronograph with a 40.9 mm case, about 12.3 mm thickness, 30 m water resistance, sapphire crystal, and calibre 79350. That calibre is a modified Valjoux 7750 with a 44 hour power reserve and 28,800 vibrations per hour. The IW371743 number sits inside that family. Published spec sheets for this exact number are scarce, so confirm the dial color, strap, and any limited edition marking with IWC or a dealer archive before you compare a replica.
Case and size
Measure across the bezel from the 4 o'clock to the 10 o'clock side. A correct copy reads 40.8 to 41.0 mm. Many replicas run 42 mm or wider. Check thickness with a caliper. Anything past 13.5 mm sits high on the wrist and points to a thin stamped caseback.
Dial and subdials
- Subdial centers sit on a vertical line through the center pinion. A 7750 base can shift the 12 o'clock counter by 0.3 to 0.5 mm.
- Print on the reference is thin and level. Raised, glossy print is a mismatch.
- Applied numerals have polished edges and a flat top face.
- Hands are leaf shaped, with a flat polish and no burr at the tip.
Movement
Ask for a photo through the caseback. A 7750 based copy shows a rotor with a cutout edge and a balance at 6 o'clock. A quartz copy has no rotor at all. Movement choice drives the price more than the case finish does.
Price and risk
Replica prices for this reference run from about $250 to $600. Under $200 buys a quartz build with printed subdials. Above $500 the case, crystal, and bracelet get closer to the original. No replica carries IWC warranty or service support.
Legal note (US)
US law makes trafficking in counterfeit goods a federal crime under 18 U.S.C. § 2320. Customs can seize a shipment. A counterfeit watch has no resale value and cannot be serviced by IWC.