Strap for Perpetual Calendar 5160

No. The bracelet is integrated into the case with a proprietary attachment: no standard strap will fit. When this watch arrives at the atelier, I build the strap directly on it, millimetre by millimetre.

I work by appointment only, at <a href="/pages/casati-booking">Casati Milano</a>, Via XX Settembre 15, Milan. I bring the watch to the bench, take measurements from the actual case, and build every component by hand. There is no template: each strap is made from scratch on that specific piece.

I choose Barenia extra-souple without hesitation. It is a leather with its own character, it ages with dignity, and its natural tone works precisely with the rose gold of the case. For a perpetual calendar of this mechanical complexity, I want a leather with the same long breath — nothing showy, but something lasting.

With a quality leather and basic care, five years is a starting point, not a ceiling. Barenia in particular does not deteriorate: it transforms, absorbing the character of the person wearing it. The advice I always give is straightforward: keep it away from water, let it breathe between wearings, and avoid harsh products.

It means the mechanism calculates the length of every month autonomously, including leap years, with no need for manual correction. 'Retrograde' describes how the hands display the date: they travel along an arc and then snap back to the starting point. I have seen many complications on the bench over the years, but the precision with which Patek Philippe handles that jump still catches my attention every time I observe it up close.