The short answer
A fake IW545173 is a replica built to imitate a specific IWC reference, and the giveaway is almost never the part you notice first. It is the reference string itself, the caseback engraving, and the movement under the caseback. If a listing cannot show you all three, stop there. Most replicas in this tier get caught on the number, not the logo.
I look at the reference before I look at anything else. Sellers reuse digit strings across different cases and dials, and the mismatch shows up fast once you know what IWC's own reference list looks like.
Start with the reference number
IWC reference numbers are not random. They break into a family block and a variant code, and the variants line up with case metal, dial color, and strap or bracelet. When a listing says IW545173 and then shows a case, dial, and strap combination that does not fit that variant, the watch is a mashup. That is common with replicas made from generic parts.
Check the number against IWC's published reference list before you look at photos. It takes two minutes and eliminates most bad listings. If the seller gets defensive about it, that tells you something too.
Caseback engraving is where most replicas slip
Real IWC casebacks carry deep, crisp engraving. The letterforms have consistent stroke weight, and the spacing between the reference number and the case serial is even. On replicas, the laser etching is shallow, the font is slightly wide or slightly bold, and the serial often repeats across different listings from the same seller.
- Engraving depth: run a fingernail across it. Genuine engraving catches; printed text does not.
- Font: compare letter spacing on the reference line, not just the shape of the digits.
- Serial: ask for it in writing and check whether it shows up on other listings.
- Caseback finish: brushed and polished zones should have a hard, clean edge between them.
The movement is the hardest thing to fake well
Open the caseback, or ask for a clear photo of it. A genuine IWC movement shows a level of finish that a clone does not reproduce: even Geneva stripes, polished screw heads with a proper slot, blued screws with correct color, and rotor engraving that sits flat rather than looking stamped.
Look at the balance wheel and the winding action. A cheap automatic rotor spins loose and rattles. A well-finished movement winds with resistance that feels deliberate. Also check beat rate and power reserve claims against the actual calibre. If the seller quotes a number that does not match the movement family, that is a red flag, not a detail.
Dial, hands, and printing
The dial is where a replica looks fine in a photo and wrong in your hand. Real applied indices sit flush with a sharp edge and even lume fill. On replicas, the fill is uneven, the indices sit slightly proud, and the printing on the dial is either too thin or too heavy.
Check the date window. The date font and the alignment inside the window are consistent on the real thing. On replicas, the date sits high or low, and the font is a different weight from the rest of the dial text. Hands should be polished on the bevels with no tooling marks on the flat surfaces.
Weight, thickness, and wrist feel
Case thickness is a number replicas rarely match. A watch built on a generic movement is often a millimeter or two thicker than the real reference, and that shows up as a caseback that sits too high off the wrist. Weigh it if you can. Steel cases in this class land in a narrow range, and a replica usually misses it in one direction.
Crystal anti-reflective coating is another tell. Genuine IWC crystals have a faint blue or purple tint at an angle, with no visible haze straight on. Cheap coating looks milky or reflects like a mirror.
A quick checklist before you commit
- Confirm the reference exists and matches the case, dial, and strap shown.
- Get a clear caseback photo and read the engraving.
- Get a movement photo, and check finish quality, not just the rotor logo.
- Ask for the case serial and search it against other listings.
- Compare stated thickness and weight to the official spec.
- Check the date font and window alignment.
- Walk away if the seller will not send the photos you asked for.
The honest part
No replica in this price band is indistinguishable from the real watch, and anyone who tells you otherwise is selling something. What separates a decent replica from a bad one is consistency: the reference matches, the engraving is crisp, the movement finish holds up under a loupe, and the case proportions are right. Judge those four things and you will avoid most of what is out there.