Quick answer

A replica IW371424 copies the IWC Portugieser Chronograph: a 40.9 mm stainless steel case, a bi-compax dial with a 30-minute counter at 12 and small seconds at 6, a date window at 3, and IWC calibre 79350, a modified Valjoux 7750. A good copy matches the case diameter and the subdial spacing and sweeps at 28,800 vibrations per hour. Budget $350 to $700 for that level of finish. Anything under $200 is usually a quartz watch with a printed dial or a low-grade automatic.

Prerequisites

  • Reference photos of the exact IW371424 dial, hand, and strap combination, since IWC varies these by reference number inside the 3714 family.
  • Digital calipers for diameter and thickness readings.
  • A 10x loupe for dial print, applied markers, and hand edges.
  • A seller who sends photos of the actual unit and offers a return window.

Inspection procedure

  1. Measure the case. Diameter should read 40.9 mm. Thickness should sit near 12.3 mm; anything above 13.5 mm means a thick movement spacer and a case that sits high on the wrist.
  2. Check the subdial positions. Counters belong at 12 and 6, date at 3. Hold the photo against a reference image. Subdials that crowd the centre or sit too far out mean a wrong dial plate.
  3. Read the dial print with the loupe. The IWC wordmark and SCHAFFHAUSEN line should have even stroke weight with no ink bleed. AUTOMATIC sits above the 6 o'clock subdial.
  4. Look at the hands. Feuille leaf shape, crisp facets, no burrs at the tips. Blued hands should show a deep blue with no purple tint, which signals paint rather than heat treatment.
  5. Run the chronograph five times. Start, stop, reset. The reset hand must snap back to zero at 12 and stay there. Creep of half a second after reset points to a worn or poorly fitted reset hammer.
  6. Watch the small seconds at 6. It should sweep in eight small jumps per second, the beat rate of a 28,800 vph movement. A stutter or skip comes from the transfer gear that a converted 7750 uses to move running seconds from 9 to 6.
  7. Set the time and date. The crown should click into three clear positions. The date should flip within roughly 30 minutes of midnight, not drag across several hours.
  8. Inspect the caseback engraving. Lettering should be cut, not lasered on the surface, and the reference and serial fonts should match your reference photo.
  9. Check the strap and buckle. Alligator grain should follow a natural scale pattern, stitching should be tight and even, and the buckle engraving should be sharp.
  10. Confirm the crystal. Sapphire shows a faint blue or purple reflection from anti-reflective coating. A plasticky look or deep scratches after light handling means mineral glass.

Questions to ask before payment

  • Can you send QC photos of this exact watch, including a close-up of the dial and a timing machine reading?
  • What is the movement, a converted A7750 or a clone with a native 12 and 6 layout?
  • What is the return window, and who pays return shipping on a defect?
  • Is water resistance tested, or is the rating decorative?

Red flags

  • Photos reused from other listings or from a factory catalogue with no unit-specific shots.
  • Claims of Swiss-made parts on a watch priced under $300.
  • No return policy, or payment by gift transfer only.
  • Dial photos with a blurry date window, uneven lume plots, or a misaligned chronograph hand at rest.

Set realistic expectations

Even a strong replica IW371424 will not match the original case finishing under a loupe, and its movement will not hold service intervals the way a stock 79350 does. Treat water resistance as unproven, keep the watch away from showers and pools, and have any automatic chronograph serviced by a watchmaker who works on Valjoux 7750 derivatives. Buy the copy for the look on the wrist and judge it on case proportions, dial legibility, and a clean chronograph reset.