The short answer
A fake Calibre de Cartier 42mm is a counterfeit copy of one specific watch: the 42mm automatic Calibre de Cartier that Cartier introduced in 2010 and built around its own 1904-PS MC movement. The copies nail the silhouette from across a room. They miss the movement, the finishing, and the caseback, which is where the real watch lives. Buying or importing one in the US also carries legal exposure that most listings never mention.
What the genuine 42mm Calibre de Cartier is
Cartier launched this line as its first family of watches designed around a movement the maison built in-house. The 42mm steel references, including W7100015, are the models the replica market copies hardest.
- Case: 42mm diameter, about 11mm thick, brushed and polished steel, fluted crown with a blue cabochon.
- Movement: Calibre 1904-PS MC, automatic, roughly 48 hours of power reserve, 27 jewels, beating at 28,800 vibrations per hour.
- Dial: oversized Roman XII, central seconds, date at 3 o'clock under a magnifier.
- Caseback: sapphire display back, so the movement is meant to be looked at.
- Water resistance: modest on the standard model, 30 meters.
That display back is the whole problem for counterfeiters. You cannot hide a cheap movement behind sapphire.
Where the fakes fall apart
- Movement. Plenty of copies run quartz. Better ones use a generic Chinese automatic that beats at 21,600 vph, so the seconds hand sweeps a little slower and coarser than the real thing.
- Caseback engraving. Fonts drift. Letters sit too heavy or too thin, and reference numbers get transcribed wrong.
- Rotor finish. Real Cartier rotors are decorated. Copies often show machine marks and uneven brushing.
- Crown cabochon. Genuine spinel has depth under light. Glass or plastic looks flat and cloudy.
- Dial printing. Look at the spacing around the XII and the minute track. This is where cheap copies give themselves away first.
- Date window. Cartier's date font is specific. Copies borrow a generic numeral set.
What each one costs
A pre-owned steel 42mm Calibre de Cartier typically trades somewhere in the four to seven thousand dollar range depending on reference, condition, and whether box and papers are included. Fakes run from about eighty dollars for a quartz knockoff up to several hundred for the better automatic copies. That gap is not marketing margin. It is the movement, the finishing, and the hundreds of hours of design work the copy skips.
Legal reality in the United States
Trafficking in counterfeit goods is a federal offense under 18 U.S.C. Section 2320, and penalties scale with the number of items involved. Importing is a separate issue. Customs and Border Protection seizes counterfeit watches and can destroy them, and the personal-use argument does not create a loophole. Calling something a replica in the listing does not change what it is. It is still an infringing copy of a protected mark.
Quick tell signs if you are holding one
- Weigh it. A steel 42mm Cartier feels dense and balanced. Copies usually feel light in the hand.
- Flip it over. If there is no sapphire back, or the rotor looks unfinished, stop there.
- Watch the seconds hand for thirty seconds. A 28,800 vph movement sweeps smoothly. A 21,600 one looks slightly choppy.
- Check the crown stone in daylight. Depth versus flatness tells you a lot.
- Ask for the reference number, then compare it to the dial layout. Mismatched combinations are common on fakes.
Bottom line
If you want the shape and the name on the dial, a copy delivers that and nothing else. If what draws you to the Calibre de Cartier is the 1904-PS MC and the sapphire back, no fake gets you there, because that movement is the point of the watch. Weigh the price against what you actually get, and factor in the seizure risk if it ships from overseas.