MB&F · Horological Machines

Strap for Horological Machine N°9 HM9 Sapphire Vision White Gold / Purple

Integrated bracelet: measurements, the most common questions, and the way to a made-to-measure strap.

Integrated bracelet

The MB&F Horological Machines 91.SWL.PU is designed with a bracelet integrated into the case. For a compatible made-to-measure strap, the Casati Milano atelier builds it on your watch.

Case diameter47 mm
Reference91.SWL.PU
FamilyHorological Machines
MovementMB&F caliber HM9 Hours, Minutes | Power reserve indicator
Year2021
CaseWhite Gold, Sapphire

Spring bar

Swiss Standard universal spring bars

The right category for this model · 316L steel, all lug widths 13–26 mm

The Horological Machines 91.SWL.PU, seen from the bench

The MB&F Horological Machine HM9 features the in-house HM9 calibre with hours, minutes and power reserve indication. The movement offers time display through an unconventional reading system characteristic of the brand's creations. The reference 91.SWL.PU is part of the Horological Machines collection that reinterprets the traditional codes of mechanical watchmaking.

Frequently asked questions

Can a standard strap be fitted to the MB&F Horological Machines 91.SWL.PU?

No, a standard strap with straight bar lugs cannot be mounted on this model because the attachment is proprietary and an integral part of the case architecture. A bespoke strap is constructed directly on the watch at <a href="/pages/casati-booking">Casati Milano</a>, during a dedicated measurement and personalisation session.

How does the bespoke strap realisation work for this MB&F watch?

The craftsman at Casati Milano takes a precise measurement of the attachment directly on the watch, documenting the dimensions, geometry and inclination angles. The strap is then handcrafted to exact specifications, tested and assembled until a perfect anatomical fit is achieved.

Which leather is most suited to the character of the MB&F Horological Machines 91.SWL.PU?

For this three-dimensional sculpture in white gold, we recommend alligator, which balances the geometric complexity of the case with a measured texture; vegetable-tanned calf, for those who prefer the contrast between geometric coldness and organic warmth; or ostrich, which creates a mineral texture coherent with the contemporary essence of the piece.

How long does a bespoke strap from Casati Milano last?

A strap crafted with artisanal precision to exact measurements has a lifespan that depends on usage and maintenance, but typically exceeds 5-7 years. The perfection of the initial fit and leather quality guarantee longevity superior to standard straps, and the natural patina of the leather ages nobly over time.

What makes the HM9 movement of the 91.SWL.PU so distinctive?

The HM9 calibre is MB&F's proprietary heart, designed to express hours, minutes and power reserve indicator in a minimal and geometrically pure configuration. This movement enables the three-dimensional case architecture that characterises the entire sculpture: it is the mechanics that generate the form, not vice versa.

The next step

The right strap isn't chosen. It is built, together.

From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.

Request an appointment →

Casati Milano · Via XX Settembre 15, Milan · by appointment only