Short answer

31610 is not a Cartier model number. Cartier sells the Ballon Bleu de Cartier, and its references use a W prefix, such as W69010Z4 for the 28 mm steel model. The number 31610 does not appear in the Cartier catalog. In listings it acts as a seller SKU or a marketplace item ID attached to counterfeit Ballon Bleu watches. Cartier has not published anything about the number, and no US agency documents it. Treat 31610 as a listing code, not a watch reference.

What 31610 is

  • Not a Cartier reference. Cartier references begin with W or CRW.
  • Listings that carry 31610 describe a steel Ballon Bleu with a blue cabochon crown, 33 mm or 36 mm, with a quartz or automatic movement.
  • The same code appears against different sizes and dial colors, so it marks a seller stock item, not one specific watch.

What the Ballon Bleu is

Cartier launched the Ballon Bleu de Cartier in 2007. The case is round. A crown guard curves around the fluted crown and holds a blue synthetic spinel cabochon. Dials carry Roman numerals, a guilloché texture, and sword hands. Catalog sizes include 28 mm, 33 mm, 36 mm, 40 mm, and 42 mm, in steel, gold, and two-tone. Movements include quartz and automatic calibers.

How counterfeit versions differ

Counterfeit Ballon Bleu watches are sold online and at open markets. Reported differences against genuine pieces:

  • Cabochon. Genuine watches use a synthetic spinel with a defined cut. Copies use glass or plastic, with bubbles or an uneven dome.
  • Dial print. Roman numerals on copies show thick strokes, uneven spacing, or a Cartier signature in the wrong position.
  • Hands. Blued sword hands on copies are painted, not heat-blued, so the color reads purple or flat blue.
  • Caseback. Engraving depth and font vary. Serial numbers on copies repeat across units.
  • Crystal. Genuine watches use sapphire. Copies use mineral glass, or sapphire with distortion at the edges.
  • Movement. Quartz inside a watch sold as automatic, or an unbranded movement with no Cartier marking.

Legal status in the US

Counterfeit watches are illegal to import, sell, or traffic in the United States. 18 U.S.C. 2320 covers trafficking in counterfeit goods and carries criminal penalties, including prison time and fines. US Customs and Border Protection seizes counterfeit watches at ports of entry, and watches sit among the most seized counterfeit categories in its reports. A personal purchase carries lower legal exposure than a sale, but the item can be seized at the border, and the buyer has no recourse against the seller.

Risks to a buyer

  • No warranty. Cartier service centers do not service or authenticate counterfeit watches.
  • Water resistance is unverified. Gaskets and case construction may not match the stated rating.
  • Materials are undocumented. Gold plating thickness, steel grade, and strap leather are unknown.
  • Resale value on the legitimate market is zero.

How to check a watch

  1. Find the reference on cartier.com and compare case size, dial layout, and crown shape.
  2. Ask for the reference and serial engraving on the caseback, then compare the format.
  3. Request photos of the movement, taken through an open caseback or by a watchmaker.
  4. Have the watch inspected at a Cartier boutique or by an independent watchmaker.

The origin of the code 31610 is not documented by Cartier or by any public US source.