The short answer
A replica IW371489 is a copy of the IWC Portugieser Chronograph: roughly 41mm of stainless steel, a bicompax chronograph layout with running seconds at 6 and chronograph minutes at 12, no date window, and leaf shaped hands over Arabic numerals. The good copies use a modified Asian 7750 so the subdial positions match the original 79350. The bad ones use quartz or a stock 7750 with the wrong layout, and I can spot those from across a table.
What the reference actually is
The IW371489 sits inside the 3714 family, the Portugieser Chronograph line that IWC built from the late 1990s until the in-house 3716 generation took over. Case size is about 40.9mm, thickness around 12.3mm, sapphire crystal on both sides, and water resistance rated to 30m. The movement is the 79350, which is a Valjoux 7750 with the hour counter removed and the running seconds moved from 9 o'clock to 6 o'clock. That single design decision is why the smile shaped dial looks the way it does, and it is the thing most cheap replicas get wrong.
Dial and hand combinations change by sub-reference, so check your exact variant before ordering. Silver plated, slate, blue, and black dials all appear in the 3714 range, with either rhodium or gold toned hands and numerals. A dealer who cannot tell you which one he is shipping is a dealer worth skipping.
Movement tiers
This is where the money goes. Three tiers show up in the market.
- Quartz or 21 jewel automatic: subdials that do nothing, or a seconds hand that ticks. Avoid.
- Standard Asian 7750 in the natural layout: running seconds sit at 9, chrono minutes at 12, chrono hours at 6. Wrong dial, obvious tell.
- Modified Asian 7750 with the 79350 style layout: the only version worth wearing. Expect a slight stutter in the small seconds because an extra transfer gear drives it. That stutter exists on the original too, just less.
I ignore any listing that says "Swiss ETA 7750" without a photo of the movement. In this price bracket it usually means an Asian movement with a Swiss sounding sentence attached.
Tells I look for first
- Subdial positions. Seconds must be at 6, chrono minutes at 12. Nothing at 9.
- Case thickness. Copies often run 13.5mm to 14mm against the real 12.3mm. It changes how the watch sits under a cuff.
- No date. If there is a date window at 3, the factory copied the wrong reference.
- Hand shape. Feuille hands are broad and leaf shaped, with a crisp taper. Blunt or fat hands read as cheap.
- Printing. "IWC" and "SCHAFFHAUSEN" should be sharp, correctly spaced, and level with the subdials.
- Crystal clarity. Good reps use sapphire with inner anti reflective coating. If the dial looks milky at an angle, it is mineral glass.
Case, crystal, and strap
Polished bezel, brushed caseband, and a thin caseback with a display window is the correct recipe. Ask for a photo of the rotor engraving, since that is where lazy factories stop trying. Straps matter more than people admit: the reference ships on alligator with a steel pin buckle, and most reps arrive with embossed leather. Budget for a replacement strap and the watch improves sharply. The folding clasp versions are a bonus, not a requirement.
What to pay
Entry level modified 7750 copies land around $150 to $250 and show their seams. The tier I would actually buy runs roughly $300 to $600, with better dial printing, correct thickness, and a properly decorated movement. Above that you are paying for a name, not a difference you can see on the wrist.
Before you pay
Ask for a video with the chronograph running: start, stop, reset, twice. Check that the seconds hand at 6 sweeps and the chrono minutes advance. Confirm the case diameter and thickness in writing. Confirm the dial color and hand finish. Then decide. A replica IW371489 gets the Portugieser look right when the layout is right, and nothing else on the watch matters as much as that.