Top pick: the version built around a clone of IWC calibre 69355 in a 41 mm steel case, because that is the build that gets the IW371632's slim profile, subdial spacing and pusher feel closest to the original. The criteria below decide whether a fake IW371632 reads as a watch or as a costume piece: case profile and lug geometry, dial layout and printing quality, movement type and how it affects thickness, and the finishing on the caseback, strap and clasp. Everything else, including the box and paperwork, is decoration.

What the genuine IW371632 actually is

The IW371632 belongs to the Portugieser Chronograph family, the 41 mm steel chronograph line that IWC moved onto its in-house calibre 69355. That move is the single most important fact for anyone shopping for a replica, because it changed the case profile, the subdial layout and the view through the back. The genuine watch has a wide, thin case, two vertical subdials at 12 and 6, applied numerals and markers, leaf hands, roughly 13 mm of thickness, 30 m of water resistance and a sapphire display back showing a column-wheel chronograph finished with Geneva stripes and blued screws.

A replica that reproduces the dial but hides a thick aftermarket chronograph movement behind a solid steel back is a different product wearing the same face. Judge the outside and the inside together.

Criterion 1: Case proportions and lug geometry

This is where most fakes fail first. The Portugieser case is wide and relatively flat, with lugs that curve down sharply and a bezel that stays visually thin around the dial.

  • Pros of a good case: correct 41 mm diameter, lug-to-lug near 52 mm, side profile that slopes instead of bulging, crown and pushers that sit flush with the case band, crisp polished and brushed transitions.
  • Cons of a weak case: oversize pushers, a domed caseback that adds height, lugs that look stamped rather than machined, and polishing that rounds off the sharp edges above the lugs.

Ask for a straight-on side photograph. Thickness is the tell. If the case looks like a small cushion on the wrist, the movement inside is not a 69355 layout.

Criterion 2: Movement, thickness and pusher feel

The genuine calibre 69355 runs at 4 Hz with a 46-hour power reserve and a column wheel. Replicas generally fall into two camps: a decorated clone that mimics the 69355 layout, or a modified third-party chronograph module.

  • Pros of a clone movement: correct case thickness, subdial positions in the right places, chronograph seconds that start without a visible jump, a display back worth looking at.
  • Cons of a module movement: added thickness, subdials pushed off centre, mushy pushers, a rotor that spins loudly, and a solid back used to hide all of it.

Test the pushers in person if you can. A column-wheel chrono starts and stops with a light, clean click; a cam-actuated budget movement feels spongy and the reset can stutter.

Criterion 3: Dial, printing and subdial spacing

The dial is the part you look at a hundred times a day, so it deserves the harshest scrutiny.

  • Pros: subdials centred on the vertical axis at 12 and 6, applied numerals with real depth, hands with a proper leaf curve and a clean central pinion, crisp minute track, no visible glue around the markers, date window aligned with the aperture.
  • Cons: flat printed markers instead of applied ones, subdials drifting toward the centre, a date font that is too bold, seconds hand that stutters at low amplitude, and lume that is uneven under a loupe.

Compare the subdial diameter to the dial diameter. On the real watch the two registers are generous and sit close to the centre line. A fake with small, widely spaced subdials is usually a module movement underneath.

Criterion 4: Caseback, strap and clasp

The back is where sellers get lazy, because they assume nobody turns the watch over.

  • Pros: engraved markings with sharp, deep lettering, a sapphire crystal flush with the ring, perlage or striping on the movement plates, a strap with real alligator grain and stitched edges, a signed pin buckle or folding clasp with a firm spring.
  • Cons: shallow laser etching, a crystal that sits proud of the ring, printed rather than applied decoration on the movement, a strap that feels like cardboard, and a clasp that rattles.

Red flags in listings

  1. Photographs that never show the watch from the side or the back.
  2. One stock image reused across several listings with different specifications.
  3. Claims of a display back on a watch that clearly has an added case-back spacer.
  4. No mention of movement type at all, or a vague phrase like high grade automatic.
  5. Pressure to pay outside a trackable channel.

Which version suits which buyer

If you want the closest visual match and you plan to wear the watch with the caseback facing away from curious eyes, choose the clone-movement build in steel with the silver dial and an alligator strap, and budget for a strap upgrade. If you want a chronograph you can actually run without worrying about servicing, a simpler module-based fake IW371632 with a solid back is the cheaper, lower-risk choice, but accept the extra thickness. If you are buying to compare against a genuine watch or to photograph side by side, skip both and put the money toward handling the real thing first, because proportion errors only become obvious once you have seen the original.

Before you buy

Replica watches are counterfeits: they carry no manufacturer warranty, most watchmakers will not service them, and resale is restricted or illegal in many countries. Customs seizure is a real risk on cross-border shipping. Treat the purchase as a disposable-cost hobby rather than an investment, and judge every fake IW371632 on the four criteria above rather than on the story in the listing.