Short Answer

The Clé de Cartier small is a 31 mm round watch with a key-shaped crown set with a cabochon. A passable replica copies that 31 mm diameter, the crown profile, the sapphire crystal and the printed Roman numerals with the secret signature worked into the VII. Replica quality varies a lot between factories, so judge the watch on measured size, crown function, dial printing and caseback engraving instead of listing photos. Any replica is a copy, not a Cartier watch, and it should never be sold or passed off as genuine.

Prerequisites

  • A digital caliper, or a ruler you can read to 0.5 mm
  • A 10x loupe
  • Daylight or a bright lamp
  • The reference number from the caseback, so you can compare it with Cartier published specs

How to Check a Replica Clé de Cartier Small

  1. Measure the case across the middle, crown excluded. A small is 31 mm. A 33 or 34 mm result means you have a medium case, not a small.
  2. Inspect the crown. The clé crown has a key profile that should turn without grinding and pull out to set. The cabochon should sit flush, not proud on a glue blob.
  3. Read the dial through the loupe. Roman numerals should have clean edges, even stroke weight and no ink spread. The secret signature forms part of a numeral stroke, not a stamped add-on.
  4. Check hand alignment. Sword hands should land on the markers at 12, 3, 6 and 9, and the hour hand should reach its track.
  5. Tilt the watch to 45 degrees. Sapphire with an anti-reflective coat goes almost invisible; cheap mineral glass shows a blue or purple haze.
  6. Study the caseback. Engravings should be deep and sharp, with even letter spacing and the correct model and reference numbers for the size you bought.
  7. Work the clasp. A folding clasp should close with one firm snap, hold under a light pull and carry engraving on the blade, not just the top plate.
  8. Run the watch for 24 hours against a phone clock. Note the movement type first: Cartier used more than one caliber across the small range, so check the reference before you judge accuracy.

Flaws That Should End the Deal

  • Case measured at 33 mm or more, sold as small.
  • Crown with a plain round head and no key shape.
  • Cabochon in plastic, or set at an angle.
  • Dial print that blurs under a loupe.
  • A date window on a reference that should be time-only, or a square aperture on a round model.
  • Caseback text that is shallow, uneven or missing the reference number.

What to Ask Before You Pay

Ask for the reference number, a photo of the case on calipers, the movement type, the crystal material and the strap material. Ask whether the photos show the exact watch you will receive. Ask about the return window and who pays return shipping. If a seller will not answer those five points in writing, buy elsewhere.