Short answer
A fake Must de Cartier Tank is a counterfeit or replica version of Cartier's Tank Must or the older Must de Cartier Tank line. It copies the rectangular case and Roman numeral dial. It is not made by Cartier. The fastest tells are the case finish, dial print, blue cabochon, caseback engraving, strap, and movement. Paperwork and price matter too. A real Tank Must does not sell new for a fraction of retail, and Cartier does not honor warranty on counterfeits.
What people mean by Must de Cartier Tank
Cartier has used Must de Cartier on vintage Tank models and Tank Must on current entry-level steel watches. Sellers blur the names. If a listing says Must de Cartier Tank and shows a new-looking steel watch, check which model it is supposed to be. The reference number, case size, dial layout, and movement should match that exact model. A vague description is a warning sign.
Quick visual checks
I start with the case and dial because most fakes fail there.
- Case finish: Real Tank Must cases have crisp edges and even brushing. Fakes often show soft corners, wobbly polishing, or sharp burrs.
- Dial print: Roman numerals should be sharp and consistent. Fake dials often have thick print, uneven spacing, or a fuzzy Cartier signature.
- Cabochon: The blue crown stone should sit flush and show depth. Fakes use flat blue glass or plastic that looks dull.
- Hands: Sword hands should be clean and aligned. Look for rough edges or sloppy lume on models that have it.
- Strap: Cartier straps have clean stitching and a proper signed buckle. Fake straps often feel stiff and have weak hardware.
Caseback, serial, and paperwork
The caseback should have correct engraving depth, model and serial numbers, and a finish that matches the case. Fake engraving often looks laser-etched and shallow. Serial numbers should match the paperwork, but paperwork is easy to fake. A box and papers set is not proof. Call Cartier or a trusted watchmaker if you need verification. Do not rely on a seller's story.
Movement and feel
Many Tank Must models use quartz movements, which makes them easier to copy than mechanical watches. That does not make the copy good. A fake can keep time and still fail on case shape, crown action, dial detail, and finishing. Open the caseback only if you know what you are doing. A watchmaker can check the movement, but the outside details usually tell the story first.
Price and legal reality
If the price is far below the market for the stated model, treat it as a fake until proven otherwise. In the US, selling counterfeit goods is illegal, and Customs can seize imported fakes. Cartier will not service or warrant a counterfeit. Resale value is close to zero. That matters if you plan to sell later.
Bottom line
A fake Must de Cartier Tank can look close in photos. In hand, the case, dial, crown, and paperwork usually give it away. Know the exact model, compare details, and price the risk. If you want a Cartier Tank, buy from a seller who can prove the watch and accepts returns.