Short answer
A fake IW371480 is a copy of the IWC Portugieser Chronograph. The genuine watch has a 40.9 mm steel case, a two-register dial and no date window. Copies sell from about $80 for quartz versions to $450 for versions built on a modified Valjoux 7750. Three checks settle most cases: case thickness, what the hand at 6 o'clock does, and the engraving on the movement.
Numbers below come from IWC reference data and from dealer listings. Confirm the exact dial variant before you compare details, because the 3714 line ran for years with dial and hand changes.
Genuine baseline for reference IW371480
- Case: stainless steel, 40.9 mm diameter, about 12.3 mm thick
- Crystal: sapphire, front and back. The caseback is an exhibition type.
- Movement: IWC caliber 79350, based on the Valjoux 7750, 28,800 vph, 31 jewels, about 44 hours of power reserve
- Dial: chronograph minute counter at 12, running seconds at 6, leaf hands, applied markers
- Water resistance: 3 bar
- Functions: hours, minutes, small seconds, chronograph with a 30 minute counter. No date.
Copy tiers and prices
- Quartz, $60 to $120. The seconds hand ticks one step per second. The pushers start a printed hand or do nothing.
- Stock 7750, $150 to $250. Beat rate matches at 28,800 vph, but the gear train puts running seconds at 9 o'clock.
- Modified 7750, $250 to $450. Running seconds moved to 6, counter at 12. Sellers call this tier first copy or super clone.
Six checks
1. Thickness
A 7750 chronograph needs depth. A copy that measures under 11 mm at the case middle carries a quartz movement. Ask for a caliper photo with the caseback flat on a table.
2. Hand at 6
On the genuine caliber 79350 that hand sweeps in small increments. A hand that jumps one step per second is quartz. A hand frozen at 12 is a decorative plate.
3. Date window
The 3714 reference has no date. Any opening at 3 o'clock means a copy case or a different reference.
4. Movement finish
The exhibition caseback shows the movement. Look for engraving on the rotor and bridges, striped finishing and blued screws. Blank plates and printed text are common on copies.
5. Caseback text and serial
Reference numbers and serials on copies are etched, not lasered, and the font drifts. Compare the same string against IWC records.
6. Weight and strap
A steel 40.9 mm case on a leather strap sits near 80 g. Copies under 65 g use a thinner case or a hollow clasp. Strap stitching on copies runs uneven at the keeper.
What the price does not tell you
Price tracks the movement, not the dial. A $300 copy with a modified 7750 keeps time within a few seconds a day and needs service like any 7750. A $90 quartz copy keeps better time but fails the first check any buyer runs: the sweep of the seconds hand. Neither holds value. Neither survives a swim.
Before you pay
- Ask for a video of the chronograph start, stop and reset.
- Ask for a timegrapher reading: rate, amplitude and beat error.
- Confirm the return window in writing.
- Pay by a method with a dispute process.