Short answer
Replica iw371765 is a seller label for a copy of an IWC Portugieser Chronograph. IWC builds the Portugieser Chronograph 41 in a 41 mm case with the in-house calibre 69355, and the IW3716 reference group covers that line. I could not confirm a current IWC product page for the number IW371765 itself, so the last digits point to a dial or case variant rather than to a separate model. Sellers use the number for steel cases with silver, blue, green or black dials.
The genuine watch behind the number
The Portugieser Chronograph has two subdials: a 30-minute counter near 12 and small seconds near 6. A date window is absent on most versions. The case measures about 41 mm across and about 13 mm thick. Lug width is about 20 mm. Current models use a sapphire front crystal and a display back, and the standard references ship on alligator leather straps.
Water resistance covers splashes. IWC does not rate the Portugieser Chronograph for swimming or diving.
Movement
Calibre 69355 is an automatic chronograph. It runs at 4 Hz (28,800 vibrations per hour) and carries a 46-hour power reserve. Earlier Portugieser Chronograph references (IW3714) used a modified Valjoux 7750 base, and that change is one reason collectors track the reference number.
Replica tiers and the movements inside
Entry tier (about $80 to $150)
Cases are plated brass or low-grade steel. Movements are quartz or basic automatic. Subdial spacing and hand length differ from the original.
Mid tier (about $200 to $400)
316L stainless steel cases, sapphire-coated glass and automatic movements copied from the Valjoux 7750 pattern. That base brings a third subdial at 9 on many dials, so the layout shows three counters where the original has two.
Top tier (about $450 to $800)
Cases sit closer to 41 mm with correct thickness, AR-coated sapphire and decorated Chinese chronograph movements built for the two-register layout. Caseback engraving and rotor text change by batch.
Checks before buying
- Count the subdials. Two is correct. Three points to a 7750 base.
- Measure the case. 41 mm across, 13 mm thick.
- Check hand length. The 30-minute hand should reach the minute track.
- Turn the crown. Winding should feel smooth, with no grinding.
- Run the chronograph for an hour and compare the 30-minute counter with a phone clock.
- Read the caseback text. Blurred engraving shows low tooling quality.
Price and market notes
Replica listing prices for this shape sit between about $80 and $800, with most sales in the $200 to $400 band. Used genuine IWC Portugieser Chronograph 41 models trade for several thousand dollars, so no replica price overlaps the real watch.
What the number does not tell you
No public IWC document I found ties IW371765 to a named dial variant. Replica makers reuse reference numbers across batches, so two watches sold under the same number can differ in case, dial and movement.