Quick answer
A replica IW371484 is a copy of the IWC Portugieser Chronograph. The genuine reference uses a 40.9 mm steel case, a two-register dial and a Valjoux 7750 based movement. Replicas sell for $200 to $600. The gap between a good copy and a poor one sits in three places: case thickness, subdial spacing and dial printing.
What the genuine reference does
IWC built the IW3714 family around caliber 79350, a Valjoux 7750 base with IWC finishing and a chronograph module. Case width is 40.9 mm. Case height is 12.3 mm. Sapphire crystal front and back. Water resistance 30 m. Two subdials: chronograph minutes at 12 and running seconds at 6. No date window. Leaf hands, applied numerals, railway minute track.
Dial color and case metal vary inside the IW3714 block. Confirm the exact version of the IW371484 with the seller before you compare photos.
Case and thickness
Most replicas run 41 mm to 42 mm wide and 13 mm to 14.5 mm thick. Ask for a photo of the watch on a caliper. A 1 mm height error shows on the wrist and it shows at the caseback lip. Check the lug shape: genuine lugs curve down, many copies cut flat.
Movement check
Two movements appear in the market. The common one is an Asia 7750 clone. The other is a decorated copy with fake stripes and fake engraving. The Asia 7750 beats at 28,800 vph and holds 44 hours of power reserve.
- Start the chronograph and let it run 10 minutes. The counter at 12 must advance.
- Reset to zero. Both hands must snap back together.
- Shake the watch near your ear. A loose rotor rattles.
- Set the time and check the crown for wobble in the winding position.
Dial details
Look at four points. Subdial ring printing should be crisp and thin. The minute hand should reach the minute track. The IWC logo should sit level and match the numeral weight. Numerals at 12 should show sharp inner corners. Poor copies print heavy subdial rings and fit short hands.
Caseback and engraving
Check the reference number, the serial and the movement engraving. Engraving depth varies by batch. A shallow laser etch with a gold fill is a common sign of a low tier build.
Price and legal risk
Replicas are counterfeit goods. Sale and import are illegal in the US, and CBP seizes shipments. IWC will not service a replica, and parts do not swap with the genuine watch. Resale value is close to zero. Treat the money as spent.