If you are searching for a fake IW371745, the buying advice is blunt: do not buy one. A counterfeit IWC Portugieser Chronograph cannot be serviced by the brand, holds no resale value, can be seized in transit, and often costs more across five years of ownership than the price gap suggests. If you want the look of the reference, buy a genuine pre-owned example from a dealer who offers a written inspection and return window, or choose an honest hommage design that does not copy the trademarks. If you already own an IW371745 and want to know whether it is real, use the checks below as a first pass, then have a watchmaker open the case.

What the reference number actually tells you

IW371745 is one reference inside the IWC Portugieser Chronograph 3716 family. Reference numbers encode a specific combination of case metal, dial, hands, and strap, so two watches can share a case family and differ in dial color, finishing, and strap. That matters when you compare a watch to photos: a listing that shows a different dial variant, or a strap that does not match the reference, is showing you either the wrong watch or a copy. Pull the exact reference data from the brand catalog before you judge anything else.

Authenticity checks that matter

  • Case dimensions. The 3716 family sits near 41 mm across and roughly 13 mm thick with a 20 mm lug width. Measure with calipers instead of trusting a listing. Replica cases often run slightly thick, and the lugs look heavier from the side.
  • Movement view. Genuine 3716 chronographs use an in-house automatic chronograph movement from the 69300 family with a column wheel. You should see a decorated rotor with correct engraving and a balance running at 4 Hz. A generic 7750-derived movement with the rotor screw in the wrong place is the single most common tell.
  • Dial and subdial geometry. Subdial spacing, the position of the date aperture, and the thickness of the applied markers are hard to copy well. Print quality is a quick test: genuine printing stays sharp under a loupe, while replica printing shows ragged edges and uneven ink.
  • Crystal and coating. Genuine sapphire carries an anti-reflective coating on both faces and stays readable at an angle. Many replicas use a single-side coating that washes the dial out under bright light.
  • Caseback stamping. Reference numbers and hallmarks are stamped with consistent depth and a clean font. Compare the stamping directly against dealer or catalog photos of the same reference.
  • Crown and pushers. Check thread feel, pusher travel, and the crisp reset of the chronograph. Vague, gritty pushers point to a cheap movement and poor assembly.

Parameter bands worth memorizing

For the 3716 family, expect a case in the low 40 mm range, a thickness around 13 mm, a 20 mm lug width, an automatic column-wheel chronograph with roughly 46 hours of power reserve, and a sapphire crystal front and back on most variants. Confirm every number against the exact reference, because a single millimeter of difference is often the gap between a genuine case and a copy.

Red flags in a listing

  • A price far below the going rate for that reference and condition.
  • Stock photos only, with no movement photo, no caseback photo, and no serial visible.
  • Payment by wire, crypto, or gift card, with no refund option.
  • A seller who refuses third-party authentication or a return window.
  • Marketing language such as 1:1, super clone, or AAA grade.

Why the fake costs more in the end

Counterfeit watches skip testing, so water resistance claims are guesswork. Brand service is refused, parts for copied movements are often unavailable, and an independent watchmaker may decline the job or charge more than the watch is worth. Resale is close to zero. Imported counterfeits can also be seized, and the buyer loses both the watch and the money.

FAQ

Is buying a fake IW371745 illegal?

Trademark counterfeiting is illegal in the United States, and imported counterfeit goods are subject to seizure. Personal purchases carry less exposure than trafficking, but the goods can still be confiscated with no refund.

Can a replica IW371745 be serviced?

An independent watchmaker may service a common copied movement, but brand service is not available and genuine parts will not fit. Once it stops, repair options are limited and costly.

How do I verify a genuine one?

Get the reference specifications from the brand, have a watchmaker inspect the movement and case, and buy only with a written return window. Ask for dated photos of the serial, caseback, and movement before you commit.

Are hommage watches a legal alternative?

Yes, when a design avoids the trademarked name, logo, and trade dress. Hommage watches offer a similar look without the legal, service, and resale problems of a counterfeit.