Audemars Piguet returned to Watches and Wonders this year after a six-year absence, and the Royal Oak Jumbo Extra-Thin Openworked 16204XT is one of the clearest indications of why the return mattered. The 39mm reference is the first production Royal Oak Jumbo in titanium, the first to use Bulk Metallic Glass on the bezel and caseback, and it is not a limited edition, which is perhaps the most notable fact of all.
The reference is 16204XT. The case is 39mm across and 8.1mm thick. The mid-case is satin-brushed Grade 5 titanium. The bezel, the caseback frame, and the twelve studs on the bracelet are made from BMG, a palladium-based amorphous alloy. Everything else, including the bracelet links and the clasp, is titanium.
What BMG is, exactly
Bulk Metallic Glass is an engineering term for a metal that has been cooled quickly enough from the liquid state that the atoms do not have time to arrange themselves into a crystal lattice. The result is a solid that retains the disordered atomic structure of a liquid, which gives it properties no ordinary metal can match. It can be polished to a harder, mirror-like finish than conventional alloys, resists scratches better than most watchmaking materials, and, because it has no grain boundaries, does not develop the micro-roughness that normally dulls polished steel over time.
AP has used BMG before on a few experimental pieces, but Monochrome's introduction to the 16204XT frames this reference as the first time the material appears as a structural element on a standard production Royal Oak. SJX's hands-on describes the polished bezel surface in person as closer to black chrome than to polished steel. The difference only really reads in reflection, which is part of why the reference was shown at the fair with strong overhead lighting.
The movement
The 16204XT runs Calibre 7124, AP's openworked extra-thin movement introduced in 2022. Thirty-one jewels, 211 components, 28,800 vibrations per hour, central rotor, 57 hours of power reserve. The architecture is rhodium-toned with visible ruby jewel settings, and the bridges carry traditional hand-polishing on the chamfers rather than industrial brushing.
SJX's technical notes observe that the openworked layout was designed specifically for the Jumbo case and has not been scaled up or down, which is consistent with AP's recent practice of building movements around specific case architectures rather than adapting a shared base. The central rotor is skeletonised to match the dial-side openwork, and the escapement is visible through the caseback in the same rhodium tone.
Why titanium matters here
The Royal Oak Jumbo has been produced in steel, yellow gold, rose gold, platinum, and white gold. There has never been a titanium-cased Jumbo in continuous production. Element in Time's launch coverage reads the material choice as a response to the weight question specifically: a Jumbo in titanium is 40 to 50 percent lighter than the same watch in steel, and with the openworked dial removing mass from the centre of the case, the whole watch sits considerably higher on the wrist than its equivalent gold or steel references.
There is also a colour question. Titanium and palladium-based BMG read similarly under direct light but quite differently under shadow: the titanium carries a cool grey tone, while the BMG leans silver-white. The two-tone effect is not overt, but it is there, and it is the sort of thing that collectors will either love or find excessively understated depending on taste. Monochrome's closer look lands on "quietly luxurious" as the summary.
The decision not to make it a limited edition
In the current market, a new Royal Oak variant in a novel material would typically arrive as a limited edition of somewhere between 50 and 500 pieces. AP has chosen not to do that. The 16204XT is a regular-production reference, joining the steel 15202ST and the platinum 15202PT in the Jumbo line. Italian Watch Spotter's launch roundup notes that pricing is on request, which is standard AP practice for non-limited references at this level.
The commercial read is that AP is treating the 16204XT as a platform for the Jumbo line rather than as a one-time event. If the titanium and BMG combination sells well, the materials will likely migrate into other Royal Oak references over time. If it does not, AP has tested the waters without the dilution that a large limited edition would carry. Either way, the watch will be allocated through authorised retailers rather than through the brand's direct boutique channel exclusively, which is not always the case with openworked Royal Oaks.
Water resistance, wearability, weight
50 metres. 39mm x 8.1mm. Integrated titanium bracelet with a titanium folding clasp and BMG studs. The combination of the openworked dial (less metal in the dial plate) and the titanium bracelet (less metal overall) means the watch is lighter than the openworked yellow gold 26620, which has been the comparable-format reference in the line up to now.
The water resistance figure is worth noting because it has been a point of contention with some Royal Oak variants in recent years, particularly the extra-thin references that have gone below 50 metres to protect the movement case seal. The 16204XT holds at 50 metres, which is sufficient for the wrist-watch uses the Jumbo is actually designed for (which is to say, not diving).
Where this sits
Audemars Piguet came to Watches and Wonders 2026 with the Royal Oak Mini refresh, a 37mm Double Balance Wheel Openworked in yellow gold, the Atelier des Établisseurs programme, and two Code 11.59 openworked perpetual calendars alongside this reference. The 16204XT is not the most visually dramatic piece in that lineup (the yellow gold Double Balance Wheel probably holds that slot) and not the most technically novel (the Atelier programme's collaborative construction is more of a structural departure). What it is, instead, is the piece that tells you how AP is thinking about the Royal Oak Jumbo going forward.
The Jumbo is the reference from which everything else in the Royal Oak line descends. Putting it in titanium with BMG accents, at standard production rather than in a capsule, suggests that AP is widening the range of what counts as a Jumbo rather than narrowing it around collectible scarcity. For a line that has been accused, often fairly, of trading too much on its own history, that is an interesting direction.
Sources: Monochrome Watches introduction to the 16204XT; SJX hands-on and technical notes; Element in Time launch coverage; Time and Watches writeup; Italian Watch Spotter's 2026 novelties roundup.
