What an IW371642 replica is
The IW371642 is IWC's Portugieser Chronograph in stainless steel: a case of about 41 mm, a silver-plated dial with the two-register layout, and the calibre 79350 inside. A replica of this reference is a third-party copy, not a watch IWC made. The reference is out of production, so genuine examples now sit in the secondhand market beside replicas, redials and part-swaps. That mix is why the same question keeps coming up: is this watch the real thing or a fake?
Numbers to check first
- Case width about 40.9 mm, thickness near 12.5 mm.
- Two subdials: chronograph minutes at 12 o'clock, small seconds at 6.
- Calibre 79350, a Valjoux 7750 derivative, 28,800 vph, about 44 hours of power reserve.
- Sapphire crystal front and an exhibition caseback.
- Water resistance rated to 3 bar.
- Silver-plated dial with applied numerals and markers.
If a listing misses one of these numbers, slow down before anything else.
Six checks, in order
- Measure the case with calipers. A genuine 3716 comes in near 12.5 mm thick; most replicas add 1 to 2 mm because the copied movement sits deeper in the case.
- Weigh the watch. Steel 3716s land in a narrow band for their case size. A watch that feels light for its bulk points to a plated brass or thin-walled case.
- Read the dial printing under a loupe. The IWC signature and the Schaffhausen line should be sharp, level and spaced with no halo around the letters. Replica printing often looks a touch bold or sits high.
- Study the subdials. The minute counter at 12 and the small seconds at 6 must line up on the vertical axis. Spacing errors are the most common giveaway on 7750-based copies.
- Look at the date window. The aperture should have a sharp bevel and the disc should sit flat, not sunken into the dial.
- Check the caseback engraving and the movement finish together. Reference numbers, the sapphire ring and the rotor decoration should all read as one quality level. Mixed quality signals a franken watch.
Where replicas fall short
Three areas give copies away. The movement is the first: a copied 7750 runs, but the winding feel, the pusher travel and the rotor noise seldom match a serviced 79350. The finishing is the second: brushing on the lugs, the polished bevel and the crown engraving all show hand-work on the real watch. The dial furniture is the third: applied numerals on a genuine piece catch light along a crisp edge, while copies look flat at the same angle.
Buying notes
- Ask for a timed video with the chronograph running and the seconds hand resetting to zero.
- Request close-ups of the caseback and the movement, not a stock photo.
- Compare the caseback reference and serial against IWC paperwork or a service record.
- Budget for a service. A 7750-based movement needs one every few years.