Answer
IW371625 is an IWC reference number in the Portugieser Chronograph line. A fake copies the case and dial, then swaps in a cheap chronograph movement. Four checks settle it: movement, caseback engraving, dial printing, price. Genuine Portugieser Chronographs sell new for about $7,700 to $8,400. Listings at $150 to $700 are replicas.
Specs the real watch must match
- Case: stainless steel, 41 mm across, about 13.1 mm thick
- Crystal: sapphire front and back
- Movement: IWC Caliber 69355, automatic, column wheel chronograph
- Frequency: 28,800 vph (4 Hz)
- Power reserve: about 46 hours
- Dial layout: 30 minute counter at 12, small seconds at 6, date at 3
- Water resistance: 3 bar (30 m)
IWC does not publish a public spec sheet for every reference variant. Details for IW371625 alone, such as dial color and production run, are not documented in one place. Confirm with IWC service before you buy. If a listing for IW371625 shows a case other than 41 mm or a quartz movement, the reference number on the ad is wrong.
Movement
The 69355 is in house. Under the display back you see Geneva stripes on the bridges, perlage on the base plate, blued screws, and a rotor marked with the IWC logo. Counterfeits use a Chinese 7750 clone or a modified Seagull caliber. Signs: a rotor that rattles, a date that flips at 11:50 pm instead of near midnight, pushers that feel soft, and a 12 hour totalizer where the real watch has small seconds.
A timegrapher reads beat rate in minutes. A 7750 clone also runs at 28,800 vph, so beat rate alone proves nothing. Look at finish and engraving instead.
Caseback and engraving
Genuine engraving is cut into the metal. Letters have depth and sharp edges. Fakes use laser marking that sits on the surface and looks grey under a loupe. Check these items: reference number, serial number, "Probus Scafusia", "Sapphire Crystal", "3 bar", "Swiss Made". Common errors include a wrong font for the numeral 1, uneven spacing, and a serial number with no record at IWC service.
Dial and hands
Genuine applied numerals have polished bevels that catch light on one edge. Feuille hands are thin and taper to a point. Printing under a 10x loupe shows solid edges. On fakes the subdial rings sit flat, the date window is off center, and the printing bleeds into the dial finish.
Price and paperwork
A box and papers cost a counterfeiter little. Serial numbers on the card can be copied from a real watch listed online. Call IWC service with the serial before you pay. A service estimate from IWC is the cheapest authentication test.