Short answer

Cartier has never sold a watch called the Tank Must Solo. The Tank Solo was a steel quartz model sold from about 2004 to 2021. Cartier replaced it with the Tank Must in 2021. Sellers join the two names so one listing covers both search terms. A fake Cartier Tank Must Solo copies the look of a steel tank watch. The copies give themselves away in five places: case thickness, dial print, crown cabochon, case back engraving, and bracelet construction.

Tank Solo and Tank Must: what changed

The Tank Solo used a flat case with a stepped bezel and a quartz movement. The Tank Must kept the rectangular Tank shape and changed the case profile, the dial, and the strap range. Cartier lists three steel Tank Must sizes:

  • Small: 29.5 mm x 22 mm, quartz caliber 157
  • Large: 33.7 mm x 25.5 mm, quartz caliber 157
  • XL: 41 mm x 31 mm, automatic caliber 1847 MC

Cartier gives 6.6 mm as the case thickness for the Small and Large quartz versions. The Solarbeat version uses a photovoltaic movement; Cartier states an average lifespan of 16 years for it. US list prices for the steel quartz models sit in the low thousands of dollars and move with each collection update.

Points to check on a replica

  1. Cabochon. Genuine Tank Must crowns carry a blue synthetic spinel. Copies use glass or dyed plastic. Glass looks clear under a loupe; spinel holds a deeper blue with a small facet.
  2. Case back. Genuine backs carry the reference, a serial number, the Cartier name, "Swiss Made", and a water resistance mark of 3 bar. Engraving depth is even. Replica engraving is shallow, and the same reference and serial pair repeats across many units.
  3. Dial print. Roman numerals on a genuine dial have sharp inner corners. The "Swiss Made" line at 6 o'clock is thin and sits close to the minute track. Replica print is thicker and the numerals sit uneven against the track.
  4. Hands. Genuine hands are polished steel with sharp edges. Copy hands show file marks on the sides.
  5. Bracelet. Cartier uses solid links and screws cut for a driver. Copy steel bracelets use folded end links and pins, and the links move with more play.
  6. Movement. A watchmaker can open the back and read the caliber marking in under a minute. Caliber 157 is the genuine quartz unit in the Small and Large.

Legal status in the US

Trafficking in counterfeit goods is a federal crime under 18 U.S.C. 2320. A first offense carries up to 10 years in prison. A second offense carries up to 20 years. Civil claims fall under the Lanham Act, which sets statutory damages up to $2,000,000 per counterfeit mark per type of goods when the use is willful. US Customs and Border Protection seizes counterfeit watches at the border, and personal use is not an exemption. Cartier does not service watches that carry counterfeit marks.

Buying used

Ask for the reference number, the serial number, and photos of the case back. Match the reference to the size and the dial. Request a service record or a receipt from an authorized dealer. A watchmaker with a Cartier parts account can confirm the caliber. A price far under the Cartier list price for the same reference points to a copy, a stolen piece, or a watch with a replaced movement.