Short Answer

The Audemars Piguet ref 5402 is the Royal Oak Jumbo, released in 1972. Replica versions copy the 39 mm octagonal case, the eight hex screws on the bezel, and the Tapisserie grid dial. Most replicas use a different movement. That changes case thickness, date position, and winding feel. A ref 5402 replica gets the look close and the mechanics wrong.

What the Original Ref 5402 Is

  • Reference 5402ST, stainless steel, launched at Basel in 1972.
  • Case width 39 mm. Case thickness about 7.5 mm.
  • Caliber 2121, automatic, 3.05 mm thick, 19,800 vibrations per hour, about 40 hours of power reserve.
  • Petite Tapisserie dial, a raised grid of small squares.
  • Signature at 12 o'clock, the word Automatic at 6 o'clock.

Audemars Piguet does not publish total production for the 5402. Estimates in auction catalogs and collector press vary by source.

Movement Groups in Replicas

  1. Miyota 9015 or Seiko NH35. Easy to service. Beat rate, rotor shape, and thickness differ from the 2121.
  2. Clones of the ETA 2892. Thinner than the Miyota. Date wheel font and date window height differ from the original.
  3. Copies of the 2121 layout. Sold in small numbers at high prices. Rate, finish, and winding feel still differ from a genuine 2121.

The 2121 traces back to a Jaeger-LeCoultre base, caliber 920, used by three brands in the 1970s. No replica uses that base.

Checks Before Payment

  • Thickness. Use calipers. A genuine 5402 measures about 7.5 mm. Many replicas measure 9 mm to 11 mm.
  • Dial grid. Original squares are cut and finished by hand. Replica grids show soft edges under a loupe.
  • Date window. Sits at 3 o'clock. Compare the font weight against photos of a known original.
  • Hex screws. Slots on most originals line up with the case center line.
  • Hands. Originals show polished bevels on the sides of the hands.
  • Caseback. Original engraving is deep. Replica engraving is shallow and laser-cut.
  • Weight. Steel originals fall in a narrow range. A light case points to a different alloy.

Price Ranges

Auction results for original 5402ST watches run from about 50,000 USD to above 200,000 USD. Series letter, dial type, and service history set the price. Replica prices run from the low hundreds to the low four figures in USD. A replica holds no collector resale value. Parts for a replica are not standard, so service is hard to arrange.

Unknowns

Replica sellers do not publish movement origin, case alloy, or factory name. Ask for caliper photos of case thickness, lug to lug, and weight before you pay. If a seller cannot supply those numbers, treat the listing as unverified.