How to Spot a Fake Cartier Tank Must Large

The Cartier Tank Must Large is one of the most copied steel watches on the secondhand market. If you are checking one, start at the caseback. A genuine Large carries a unique serial number and a reference number, and both should match the certificate that came with the watch. Next, measure the case. The Large runs about 33.7 mm by 25.5 mm, and most counterfeits are wider or half a millimeter to two millimeters thicker than the real profile. Then look at the dial. The Tank Must Large shows hours and minutes only, with no seconds hand. A running seconds hand is the quickest sign the watch is not genuine.

What You Need

  • A 10x jeweler loupe
  • Digital calipers
  • A bright, angled light source
  • The box, certificate and warranty card, if the seller has them
  • Access to a watchmaker or a Cartier boutique

Checks, Step by Step

  1. Read the caseback engraving. Genuine Cartier engraving is crisp, shallow and even. Fakes are often laser cut too deep or filled with paint that sits above the surface.
  2. Compare the serial and reference numbers against the certificate and warranty card. Numbers that do not match, or a certificate printed on flimsy stock, point to a counterfeit.
  3. Measure the case with calipers. Record length, width and thickness, then compare them with the published specs for the exact reference.
  4. Check for a seconds hand. If the watch has one, or a cutout in the dial for a sub-dial, it is not a genuine Tank Must Large.
  5. Inspect the dial printing. The word CARTIER should be sharp with even letter spacing, and the roman numerals should be clean at the edges. Fuzzy paint or a logo that floats off the dial line is a fake.
  6. Study the crown. The cabochon should be a blue synthetic spinel set flush into the crown. Counterfeits use plastic or cloudy glass, and the stone usually sits too high.
  7. Look at the hands and crystal. Blued steel hands, no tool marks on the case flanks, and no dust trapped under the sapphire crystal.
  8. Examine the strap and buckle. Stitching should be tight and uniform, and the buckle hallmark should be stamped, not cast with visible mold lines.
  9. Have a watchmaker open the case. The movement marking, finishing and battery clamp are hard to copy well.
  10. Take the watch to a Cartier boutique or authorized service center. Counterfeits are refused for service, and a genuine serial can be traced to prior service records.

Why These Checks Matter

Counterfeit watches are illegal to sell or import in the United States, and they carry civil and criminal penalties for the seller. A fake also gives you nothing in return. No brand service, no parts support, no warranty, and no resale value. Buyers who skip the caseback and dial checks usually find out at the service counter, where the watch is refused and the money is already gone.