A fake Fifty Fathoms 43mm is a replica of Blancpain's 43 mm dive watch, most often modeled on the Bathyscaphe line, and it differs from the genuine article in case finishing, bezel action, dial printing, and movement. The 43 mm size matters because it wears closer to a standard sports watch than the 45 mm Fifty Fathoms Automatique, which is why this diameter gets asked about so often in replica circles.

What "43mm" actually refers to

Case diameter is measured across the case at its widest point, crown excluded. Two watches can both be listed at 43 mm and still wear very differently, because lug to lug length and case thickness change how a watch sits on the wrist. A replica seller who quotes only the diameter is giving you a partial spec sheet.

In the Blancpain catalog, 43 mm references belong mainly to the Bathyscaphe family. The classic Fifty Fathoms Automatique is larger at 45 mm, so a listing that calls a 43 mm watch a "Fifty Fathoms" and shows Bathyscaphe styling is usually describing the same design lineage, not an error.

Genuine reference points worth knowing

You cannot judge a replica without knowing what the original does. On the genuine 43 mm Bathyscaphe, the broad specifications are:

  • Case: 43 mm steel, titanium, or ceramic depending on reference, with a thickness in the 13 mm range.
  • Bezel: unidirectional rotating dive bezel with a sapphire or ceramic insert, depending on the version.
  • Water resistance: rated to 300 m on the dive models.
  • Movement: Blancpain caliber 1315, a three-barrel automatic with a power reserve of about five days.
  • Caseback: sapphire display on some references, solid on others.

Those numbers give you a checklist. If a replica is listed at 15 mm thick, or the bezel insert is printed rather than cut, you already know where the corners were cut.

Replica, homage, counterfeit: the difference matters

  • Homage: a watch from a different brand that borrows dive watch styling but carries its own name and logo. Legal to buy and sell.
  • Counterfeit: a watch that carries another company's trademarks, including the dial logo and model name. Illegal to sell or import in the US.
  • Replica: in legal terms, the same thing as a counterfeit. The word softens the description, not the status.

A fake Fifty Fathoms 43mm falls in the second and third categories, because the dial carries Blancpain branding.

What to inspect on a 43 mm Fifty Fathoms replica

  1. Case finishing: look for sharp lug edges, uneven brushing, and polished bevels that stop short of the lug tips.
  2. Bezel action: the triangle at 12 should line up with the dial marker. Sloppy alignment is the most common flaw on this model.
  3. Dial printing: check the depth rating text and the logo under magnification. Blurred edges and uneven spacing show up fast.
  4. Lume: uneven application around the indices, or a bezel pip that glows a different tone than the dial.
  5. Crown and threads: gritty threading and a crown that does not seat flush are recurring issues on replicas.
  6. Caseback and movement: engraving depth, rotor noise, and whether the stated movement matches what is visible.
  7. Thickness and weight: weigh the watch and measure it. Oversized cases are the easiest tell.
  8. Date wheel: font, magnification, and centering in the window.

Is a fake Fifty Fathoms 43mm waterproof?

Treat it as splash resistant at best. Gaskets on replicas are not tested to the same standard, and a dive rating on the dial of a counterfeit is a copy of the original spec, not a measurement of the watch in your hand. Do not swim or dive with one, and do not assume a watchmaker can restore the seal.

US legal and import considerations

Counterfeit watches carrying a registered trademark are subject to seizure by US Customs and Border Protection, and importing them can expose the buyer to civil penalties. Reselling one is a separate and more serious problem under trademark law. There is also no service path: authorized watchmakers will not touch a counterfeit, and genuine parts generally do not fit.

The short version

A fake Fifty Fathoms 43mm copies a well-regarded dive watch at a size many people find comfortable, and the quality gap shows up in exactly the places you would expect: bezel alignment, dial print, case finishing, and movement. Know the genuine specs before you compare, understand that the legal risk sits with the trademark, and treat any water resistance claim on a replica as marketing rather than engineering.