Reference 5840P-001 — Cubitus Perpetual Calendar Skeleton
The Cubitus collection, introduced in October 2024, established a new expression of sporty elegance within Patek Philippe's portfolio, and Reference 5840P-001 is its first grand complication. The case is 950 platinum, 45mm in diameter and 10mm in total height, a notably restrained profile for a perpetual calendar. A baguette-cut diamond is set into the bezel at six o'clock, consistent with Patek Philippe's practice on platinum models, the cut chosen to harmonise with the rectilinear geometry of the case.
The movement is the new caliber 28-28 Q SQU, designed from the outset as a square with rounded corners, measuring 28.5 x 28.5mm, so that its shape mirrors the case architecture above it. The movement is skeletonised, with the openworked plates and bridges echoing the horizontal linear motif embossed on the Cubitus dials. A monochrome rhodium-plated finish extends across all movement components, including the 22K gold mini-rotor, with the only colour accents being the heat-blued screws and a hand-engraved Calatrava Cross varnished onto the rotor. Functional jewels throughout are set in clear sapphire rather than the conventional red, except on the lever arms where they remain red for the purposes of precision timing. The movement comprises 313 parts.
The perpetual calendar mechanism, an evolution of the 48-cam system from the caliber 240 Q family, displays the date, day, 24-hour indication, month, leap year, and moon phase across three subsidiary dials. The moon phase display is the first in Patek Philippe's regular collection to use a large-moon mechanism, with a single large-scale moon completing one rotation per lunar cycle of 29.53 days. The openworked dial, with fine laser-cut strips in blue PVD, aligns precisely with the movement beneath, reinforcing the visual continuity between case, dial, and caliber. White gold baton hour markers and hands carry a luminescent coating. The watch is worn on a navy blue Cordura composite strap with cream stitching, secured by a Cubitus fold-over clasp in platinum engraved with the collection name.