A fake IW371499 is a counterfeit copy of the IWC Portugieser Chronograph, and the fastest check is the caseback: the real watch has a sapphire display back showing an in-house IWC caliber 69355 with a column-wheel chronograph, while most fakes hide a modified Valjoux 7750, a Chinese Seagull ST19, or a quartz movement under a printed plate. Subdial spacing and the reference engraving between the lugs catch most replicas in under a minute.
What the IW371499 actually is
The IW371499 belongs to the IWC Portugieser Chronograph family, the two-register chronograph line IWC has built since 1998. That family covers dozens of reference numbers across steel, gold, and platinum cases, so metal, dial color, and strap change from number to number. IWC's own catalog page is the only reliable spec sheet for one reference; third-party listings copy each other and carry errors.
Two generations matter when you authenticate. Early Portugieser Chronographs measured 40.9 mm and ran a Valjoux-based caliber. The 2020 generation moved to a 41 mm case and IWC's in-house 69355 movement behind a sapphire caseback.
If a written spec for IW371499 disagrees with IWC's catalog on case size, metal, or movement, trust the catalog. IWC reference numbers are easy to misquote, and counterfeit sellers lean on that confusion.
How do you spot a fake IW371499?
Movement and caseback
The genuine watch has a display back, and that glass is the hardest part for a counterfeiter to copy. Look for a column wheel, a rotor engraved with IWC's Probus scallop and the caliber number, and decoration that runs in consistent lines. A quartz tick, a rotor that rattles, or a caseback with no movement visible ends the inspection.
- Real: in-house caliber 69355, about 46 hours of power reserve, column wheel, hacking seconds.
- Fake: unbranded or wrongly numbered movement, wrong rotor text, glued-on decoration plates.
Dial and subdials
The Portugieser Chronograph has two subdials: chronograph minutes at 12 and running seconds at 6. Numerals are applied metal, not printed, and they sit on a flat plane with crisp edges. On fakes the subdials sit a fraction of a millimeter off-center, the numerals look flat and dull, and the minute track thickens where it should stay even.
Case, crown, and pushers
Case finishing on the real watch moves between polished and brushed surfaces with a sharp, straight edge between them. Fakes blur that line, round off the lug tips, and use pushers that feel gritty or wobble. Check the gap between the crown and the case, which should measure the same all the way around.
Crystal and reflections
Genuine IWC sapphire carries anti-reflective coating on both faces, so the dial stays readable at steep angles with little blue or purple tint. Cheap fakes use flat mineral glass or single-coated sapphire that flashes color and distorts the dial near the edges.
Strap, clasp, and engraving
Alligator straps on real watches show an even scale pattern and a signed pin buckle or folding clasp with deep, clean engraving. Fakes use embossed leather or plastic-backed "alligator" and shallow laser-etched logos. The reference and serial numbers between the lugs should be crisp and should match the paperwork.
What does a genuine Portugieser Chronograph spec sheet include?
- Case size: 40.9 mm on older references, 41 mm on the current generation.
- Water resistance: 3 bar, which covers rain and hand washing only.
- Crystal: domed sapphire with both sides coated, plus a sapphire display back.
- Subdials: chronograph minutes at 12, small seconds at 6.
- Hands: leaf-shaped, blued or rhodium plated depending on the reference.
- Finishing: no luminous material on most references.
If a watch sold as an IW371499 claims 100 m of water resistance, a screw-down crown, or a date window at 3 o'clock, treat it as another IWC line or a fake. The standard two-register Portugieser Chronograph does not carry those features.
Why do buyers end up with fakes?
A convincing fake costs a fraction of a genuine watch, and the listing photos are usually borrowed from real auctions. Sellers push urgency, refuse escrow, and ship from a country the listing never mentions. After delivery, an IWC service center will not touch a counterfeit watch, no warranty applies, and resale value sits near zero.
Selling counterfeit goods is also a federal crime in the United States under 18 U.S.C. 2320, with penalties that reach millions of dollars for repeat offenses. Buyers rarely face charges, but they lose the money and the watch when a shipment is seized at customs.
How can you verify a Portugieser Chronograph before buying?
- Ask for a timed video of the seconds hand sweeping and the chronograph starting, stopping, and resetting to zero.
- Request macro photos of the movement, the reference engraving between the lugs, and the clasp signature.
- Match the case serial with IWC service records or an authorized dealer.
- Pay through a method with buyer protection, and get the seller's identity in writing.
- Have a watchmaker who handles IWC open the case before funds clear.
Frequently asked questions
Is a fake IW371499 worth buying?
No. IWC will not service it, it holds no resale value, and selling it is illegal in the United States. A pre-owned genuine Portugieser from an authorized seller is the only version with a paper trail and a working movement.
What paperwork should come with an IW371499?
A complete set usually means the inner and outer box, the warranty document, and the instruction manual. IWC moved toward digital warranty records in recent years, so check the production year against the warranty format the seller shows. "No papers" on a recent reference is a reason to ask more questions, not a bargain.
Can a watchmaker spot a fake IW371499 from photos?
Often yes, if the photos cover the movement, the dial at an angle, and the caseback engraving. Photos alone are not proof. A hands-on inspection with a loupe and a timing machine settles it.
Does the Portugieser Chronograph have a date window?
The standard two-register references do not. A date at 3 o'clock points to a different IWC model or a counterfeit, so verify the reference number against IWC's catalog before you judge the watch.