Short answer

A replica IW371494 copies the IWC Portugieser Chronograph. The genuine 3714 family uses a stainless steel case at 40.9 mm and IWC calibre 79350. Replicas differ in case thickness, subdial function, movement finish, and caseback engraving. No replica matches the genuine part for part. Measure and test the piece before paying.

What the number IW371494 means

IWC reference numbers carry two blocks. The first block, 3714, names the model family. The last two digits name a dial, hand, and strap combination inside that family. I could not confirm from published IWC material which dial color and strap IW371494 uses. Ask the seller for photographs of the exact piece and compare the dial layout against the 3714 family.

Genuine 3714 family specification

  • Case: stainless steel, 40.9 mm across, 12.6 mm thick
  • Lug width: 20 mm
  • Crystal: sapphire front, sapphire display back
  • Water resistance: 3 bar, about 30 m
  • Movement: IWC calibre 79350, 31 jewels, 28,800 vph, 44 hour power reserve
  • Base architecture: Valjoux 7750
  • Dial: small seconds at 6 o'clock, chronograph minutes at 12 o'clock
  • Hands: feuille shape, applied Arabic numerals

Where replicas differ

Case thickness is the first gap. The 7750 architecture is thick. IWC machines the 79350 and fits it into a 12.6 mm case. Many replicas land between 13.5 mm and 15 mm. That shows in side photographs and under a shirt cuff.

Subdial layout is the second gap. The stock 7750 places running seconds at 9 o'clock. Replicas built from stock parts keep that position. The genuine Portugieser Chronograph puts small seconds at 6 o'clock. A 9 o'clock subdial is a clear mismatch.

Movement finish is the third gap. The genuine 79350 has Geneva stripes, blued screws, and an engraved rotor. Most replicas show a plain rotor and a rough bridge finish through the display back.

Checks before you buy

  1. Measure the case across at 4 o'clock with calipers. Expect 40.9 mm without the crown.
  2. Measure thickness. Anything above 13.5 mm is thicker than the genuine.
  3. Confirm small seconds at 6 o'clock and chronograph minutes at 12 o'clock.
  4. Run the chronograph. The minute counter should advance in one minute steps.
  5. Count the beat. 28,800 vph equals 8 ticks per second. A quartz copy ticks once per second.
  6. Wind fully and set the watch down. Check the reserve at 40 hours.
  7. Read the caseback engraving. Check the font, the reference number, and the depth of the cut.
  8. Check the strap at 20 mm and the buckle marking.

Open points

I could not verify the dial color and strap for IW371494 from primary sources. Replica quality also varies by batch and by factory, and sellers reuse reference numbers across builds. Ask for current photographs with a timestamp. A photograph of one piece does not describe the next one.