Top pick: the replica 25940 worth considering is the one that gets three things right at the same time, a 39mm case with correct bezel geometry and aligned screws, subdial hands that do the same jobs as the original calibre 2385, and a bracelet whose links taper and finish match the case. Everything else, from the box and papers to whatever factory name is trending on a forum this month, is noise. The sections below break those criteria down, then cover the legal and practical side that most listings quietly skip.

What the 25940 is, and why it gets copied

The reference 25940 is the 39mm Royal Oak Chronograph from the late 1990s and 2000s, the generation before AP pushed the chronograph to 41mm and 42mm. It runs the AP calibre 2385, a Frédéric Piguet 1185 base, under a Grande Tapisserie dial and the octagonal bezel with eight hexagonal screws. Limited editions such as the City of Sails sit inside the same reference family, so dial colour and subdial treatment vary from one 25940 to the next. That variety is exactly what counterfeiters lean on, because a wrong dial can always be sold as "another variant."

Criterion 1: Case and bezel geometry

The 25940 is a small, thin chronograph by modern standards. A replica that copies a 41mm or 42mm case and calls it a 25940 is the most common failure, and it is obvious the moment the watch sits next to a real one.

• Pro: a correct 39mm case with a slim profile wears well on wrists from about 6.5 to 7.5 inches, which is where the original was designed to sit.
• Pro: eight hexagonal bezel screws that sit flush and line up with the case edges read as correct from arm's length.
• Con: stretched cases with soft bevels and over-polished chamfers look bloated and lose the sharp Royal Oak silhouette.
• Con: misaligned or proud screw heads are the fastest tell, and they cannot be fixed with a polish.

Use-case call: if you care about wrist presence on a smaller wrist, this is the criterion to spend your attention on. If the case is wrong, nothing downstream rescues it.

Criterion 2: Subdial functions and dial layout

Ask what each subdial actually does. Plenty of cheap chronographs use an Asian Valjoux 7750 derivative, which puts running seconds at 9 o'clock and stacks the chronograph counters elsewhere. If the donor movement's layout does not match the 25940 dial, the subdial hands are doing the wrong jobs, and a knowledgeable eye catches it in seconds.

• Pro: a build where the running seconds, 30-minute counter and 12-hour counter sit where the reference puts them looks coherent and photographs correctly.
• Pro: crisp Grande Tapisserie squares with sharp edges and even spacing suggest a dial worth the case around it.
• Con: printed or shallow-molded tapisserie looks flat under daylight and kills the whole effect.
• Con: calendar windows that are too large, too deep, or mispositioned are a permanent giveaway.

Use-case call: pick this criterion first if you plan to wear the watch around people who know watches. Dial execution is what they will actually see.

Criterion 3: Bracelet, clasp and finishing

The integrated bracelet is half the Royal Oak. Replicas usually get the shape roughly right and the finishing wrong, with polishing that bleeds across brushed surfaces and links that rattle or bind.

• Pro: alternating brushed and polished link faces that stay in their lanes show a maker paying attention.
• Pro: a clasp that closes with a firm click and sits flat under the wrist makes the watch wearable daily.
• Con: soft 316L links with sloppy end-link fit develop play within months.
• Con: sharp inner link edges chew into wrist hair and signal low finishing standards.

Use-case call: this matters most if the watch will be worn, not stored. A mediocre dial on a good bracelet is more comfortable than the reverse.

Criterion 4: Movement reality and servicing

No replica 25940 carries an AP calibre 2385. You are getting an Asian chronograph movement, usually a 7750 derivative or a decorated clone, and that has consequences for accuracy, chronograph reset and long-term repair.

• Pro: common Asian chronograph movements can be serviced or replaced by many independent watchmakers at modest cost.
• Pro: a running chronograph with a clean seconds reset tells you the module was assembled with some care.
• Con: decorative plates and rotor engraving fool nobody who removes a caseback.
• Con: water resistance is effectively a claim, not a specification. Do not swim in it.

Use-case call: treat any replica as a disposable object with a finite life. If you need a watch you can service for decades, this is not that purchase.

The US legal side, briefly

Counterfeit watches infringe trademarks, and US Customs and Border Protection can seize and destroy shipments of counterfeit goods. Selling replicas carries civil exposure and, in some cases, criminal exposure under trafficking statutes. Buying one does not make the item legal, and it does not create a warranty, a return right, or any recourse if the watch arrives broken.

• Pro: none on the legal side. There is no lawful resale channel and no protection if the transaction goes wrong.
• Con: resale value is effectively zero, and any dealer who offers to "authenticate" it is selling you a story.

Bottom line

If you go ahead, judge the watch on the three things you can verify: 39mm case proportions, subdial hands that match the 2385 layout, and bracelet finishing that holds up under a loupe. Skip anything sold on a single glamour photo with no caseback shot. If you want the Royal Oak look with a clear conscience and a serviceable movement, save for an honest alternative instead, because a replica 25940 is a costume, not a watch collection entry.