Short answer
The Royal Oak Perpetual Calendar reference 25659 is an ultra-thin precious-metal watch from Audemars Piguet's 1980s catalog, and every replica of it is a cosmetic copy. A good replica matches the octagonal case, the integrated bracelet, the petit tapisserie dial and the three-register calendar layout. It will not match the original's perpetual calendar mechanism, which is why the calendar subdials on nearly all copies are either decorative or driven by a cheap quartz or basic automatic movement. Judge the replica on case finishing, dial texture and thickness, not on the calendar function.
Prerequisites
- The published spec for the reference: case diameter, thickness, bracelet width
- A jeweler's loupe, or a phone with a macro lens
- A digital caliper if you plan to measure the watch after delivery
- A seller who answers measurement questions in writing before payment
How to check a replica Royal Oak Perpetual 25659
- Ask for the case diameter, case thickness and bracelet width in millimeters, and write down what you are told.
- Compare those numbers against the published spec. Copies usually run thicker than the original.
- Count the bezel screws. There should be eight, hexagonal, evenly sunk, with slots that line up with the case edge.
- Run a fingernail along the bezel bevel. A polished edge catches light in one band, not in a blurry smear.
- Tilt the dial under light and check the texture. Petit tapisserie is a raised grid, not a flat printed pattern.
- Confirm the subdial positions match the reference layout for day, date, month and moonphase.
- Study the subdial hands. They should be thin, short and cleanly printed, with no smudged numerals.
- Request a close photo of the moonphase disc, since this is the hardest detail to copy well.
- Turn the watch over and read the caseback. Check engraving depth, font and the stamped reference number.
- Wiggle each bracelet link by hand. Tight links stay quiet; loose ones rattle.
- Pull the crown and watch what moves. On most copies the calendar subdials will not advance correctly.
- Ask what the water resistance rating is, and treat any claim above 30 m with suspicion.
Red flags
- Stock photos only, with no picture of the actual watch
- No measurements given before payment
- A claim that the watch carries a genuine AP perpetual calendar movement
- A price far below the going rate for the tier being sold
- Refusal to send a caseback or crown-side photo
What the tiers look like
Budget copies use plated cases, mineral glass and printed dials. Mid-tier copies add a bezel held by real screws, a sapphire crystal and a textured dial. Top-tier copies put their money into case finishing, correct thickness and bracelet feel, and they still do not reproduce the perpetual calendar. Match the tier to how often you plan to wear the watch, and buy the best finishing your budget allows. No replica is a substitute for the genuine reference at auction, so treat the purchase as costume jewelry with a movement inside.