The short answer
On a fake IW371442 compared to the genuine, the case diameter and the crystal coating decide the outcome before the movement ever matters. Buy the tier that gets the 40.9 mm case, double-sided anti-reflective sapphire, and a correctly spaced 30-minute counter at 12 first. Anything below that fails at arm's length in daylight, and no amount of rotor engraving saves it.
What the genuine reference is
The IW371442 sits in the Portugieser Chronograph line: a 40.9 mm steel case, roughly 12.3 mm thick, a silver-plated dial with gold-plated hands and appliqués, a 30-minute totalizer at 12, small seconds at 6, a date at 3, and the calibre 79350 inside. The 79350 is a Valjoux 7750 base reworked by IWC, running at 28,800 vph with about 44 hours of reserve. That 7750 skeleton is why replica builders can copy the layout at all, and it is also why so many of them get the subdial positions wrong.
How to compare, step by step
- Measure the case with calipers. Genuine is 40.9 mm across the bezel, not the crown guards. A 41.5 mm or 42 mm replica reads fat in photos next to a ruler.
- Measure thickness at the caseback edge. Under 13 mm is close. Over 13.5 mm means the case was built around a thicker movement spacer.
- Shoot the dial straight on with a phone at 1x, then overlay it on a genuine press photo. Subdial centers must land in the same spots.
- Check the printed minute track. Genuine printing is thin and continuous, with no broken hatches at 12 or 6.
- Look at the applied gold markers at an angle. Real ones have a polished bevel that catches a hard line of light. Stamped replicas look flat.
- Put the crystal under a desk lamp. Double AR on both faces kills most reflections. Single AR leaves a blue-grey haze and a visible glare band.
- Read the date through a loupe. The font is thin and the window frame is crisp. Fuzzy edges or a bold numeral are giveaways.
- Turn the watch over and check the display back. Rotor engraving depth, perlage density, and the reference and serial fonts should match known genuine photos.
- Weigh it on a kitchen scale. Steel on alligator in this size lands near 80 g. Big deviations point to a hollow case or a cheap strap.
- Work the crown and both pushers. Winding should feel tight and even, with a firm start and stop on the chronograph.
Pick first
Top tier: correct case plus decorated A7750
This is the version to buy. It carries the 40.9 mm case, 20 mm lugs, double AR sapphire, and a 7750-based chronograph with a decorated rotor and correct dial printing. Expect a properly angled date window and subdials that sit wide and slightly high, exactly like the 79350 layout. Strap quality is usually the weak point, so budget for an alligator replacement with a signed buckle.
Option two: right case, plain movement
Same outside dimensions, undecorated movement, thinner AR. It photographs well on the wrist and poorly through the caseback. Fine if you never show the movement and you accept a slightly louder rotor.
Fake IW371442 Alternative Reviews: Top Options
Option three: budget build
Usually 41.5 mm or wider, single AR, and a dial print that thickens under magnification. It reads as a Portugieser from two meters and as a replica from thirty centimeters. Buy it only if the case shape matters more than the details.
Listing red flags
- No straight-on dial photo, only angled shots on a wrist.
- No movement photo on a watch with a display back.
- "Swiss ETA inside" claims with no calibre shot or timing figures.
- Water resistance promises above 30 m on a case you have not pressure tested.
- Strap photos that hide the buckle engraving.
Verdict
Get the case dimensions and the crystal right first, then the dial print, then the movement decoration. A fake IW371442 compared to the genuine is a five-minute check with calipers and a lamp, and the tier that passes both is the only one worth the money.