Short answer

The Must de Cartier Tank is a Cartier watch line. Cartier sold the first version from 1976 to about 2004. Those cases are sterling silver with gold plating, a finish called vermeil. Cartier brought the name back in 2021 with a steel case and a quartz movement. Counterfeit versions exist for both eras. Most fakes fail on three points: the caseback stamp, the case metal, and the dial font.

Vermeil era, 1976 to 2004

Cartier made the Must line as an entry price point under the main Tank. The cases are silver, not gold. The gold sits on top as plating.

  • Case metal: sterling silver, 925 parts per thousand. Backs carry ARGENT 925 or STERLING.
  • Plating: stamped PLAQUE OR G 20M. The 20M means 20 microns of gold.
  • Crystal: mineral glass on most examples.
  • Movement: quartz. Cartier used several calibers across the run.
  • Size: large models run about 23 mm by 30 mm. Small models run about 20 mm by 28 mm.
  • Dial: lacquer in white, cream, burgundy, black, or blue. Roman numerals. Dial text reads MUST DE CARTIER.

2021 relaunch

Cartier relaunched the Tank Must in steel. The line dropped vermeil, and a solar model joined the quartz versions.

  • Large: 33.7 mm by 25.5 mm.
  • Small: 29.5 mm by 22 mm.
  • Mini: 24 mm by 16.5 mm.
  • Movement: quartz. The Solarbeat version uses a photovoltaic movement.
  • Crystal: sapphire.
  • Dial: CARTIER print, with SWISS MADE at 6 o'clock on the models that carry it.

Checkpoints on a fake

  1. Case metal. Brass and steel cores sit under gold plate on fakes. A magnet pulls on both. Genuine vermeil is silver, so a jeweler's acid test settles it in seconds. Wear on the lugs of a fake shows yellow brass or gray base metal.
  2. Caseback text. Genuine vermeil backs carry ARGENT 925 and PLAQUE OR G 20M. Fake stamps use wrong spacing, wrong fonts, and no hallmark.
  3. Weight. Silver cases weigh less than steel cases of the same size. Brass cases weigh close to steel. Compare the head against a known watch.
  4. Dial print. Roman numerals on genuine dials hold an even stroke width. Fake dials show thick serifs, uneven spacing, and wrong letter shapes in MUST DE CARTIER.
  5. Crown. The crown holds a blue cabochon. Fakes use plastic, glass, or a stone with a flat top.
  6. Crystal and hands. The 2021 line uses sapphire. Many fakes ship with mineral glass that scratches.

Serial numbers and references

Vintage Must cases carry a serial number and a reference on the back. Serial ranges differ by year and by size. A serial that does not match the reference or the case size points to a fake. Cartier service records and auction catalogs are the places to check a number.

Legal status in the United States

Counterfeit watches are illegal to import and sell in the US. 18 U.S.C. 2320 covers trafficking in counterfeit goods. Customs and Border Protection seizes shipments at ports of entry. Buyers of a counterfeit get no Cartier service, no warranty, and no parts.