Quick answer

The Royal Oak Offshore reference 25721ST went on sale in 1993. Collectors call it The Beast. A genuine 25721 has a solid steel caseback, rubber-coated pushers and crown, eight hexagonal bezel screws that thread into the case, and AP calibre 2326. Copies of this reference show a display back, plastic pushers, decorative screws, and a Valjoux 7750 or quartz movement.

Reference facts

  • Case: 42 mm steel, thickness near 14.5 mm, water resistance 100 m.
  • Design: Emmanuel Gueit extended the 1972 Royal Oak shape drawn by Gerald Genta.
  • Movement: AP calibre 2326, base Frederic Piguet 1185, column wheel, 21,600 vph. Later Offshore references moved to calibre 3126/3840.
  • Dial: Mega Tapisserie, a stamped grid with raised squares. Colors include black, blue, white, and salmon.
  • Caseback: solid steel with engraving. Case number and movement number sit on the back.

Checks that catch most fakes

  1. Caseback. The 25721 shipped with a closed back. A sapphire display back on an offered 25721 means the case is not that reference.
  2. Bezel screws. Eight screws hold the bezel on the 25721. They pass through the bezel into the case. On copies the screws sit on the surface and the slots line up in a neat pattern.
  3. Pushers and crown. Originals carry a black rubber coating over metal. Copies use hard plastic or bare steel.
  4. Dial grid. The Tapisserie pattern is stamped into the dial plate. Copy dials use a printed grid or a decal, and the squares look flat under a loupe.
  5. Movement. A 7750-based fake ticks at 28,800 vph and the rotor swings with a wobble. Calibre 2326 runs at 21,600 vph.
  6. Engraving. Case and movement numbers on originals use a fine, even cut. Copy numbers repeat across many watches.
  7. Date window. Originals have no cyclops magnifier.

Price signal

Genuine 25721 examples sell in the tens of thousands of US dollars. Dial color, box, and papers move the number. Offers far below that range point to a copy, a franken watch, or a stolen case.

What photos cannot prove

A case opening is needed to confirm the movement. Serial checks against AP records take time and need the full number. If the seller blocks either step, stop.