Strap for Royal Oak 37 Double Balance Wheel Openworked Frosted Yellow Gold / Rainbow

The Royal Oak's attachment is an integral part of the case design: the lugs are forged in continuity with the case structure and do not accept standard straps with straight spring bars. A strap is entirely achievable, built to measure directly on the watch by <a href="/pages/casati-booking">Casati Milano</a>, where the master craftsman takes the actual lug measurements before beginning work.

The process begins with an appointment at the atelier, where the craftsman takes precise measurements of the lugs and attachment directly on the client's watch, without relying on generic dimensions. The strap is then cut, hand-stitched and finished to fit the exact geometry of the yellow gold case. The choice of leather, colour, stitching and buckle is made during the same session, with every detail agreed upon before work begins.

Yellow gold has a warm, saturated chromatic tone that pairs naturally with leathers in tobacco, cognac or mocha shades: smooth calfskin develops a patina over time that harmonises with the metal, while porosus crocodile or alligator offer a more structured grain for those seeking greater character. Ostrich, with its natural follicular pattern, is a choice for those who intend to wear this watch as an explicit personal statement.

A strap built from carefully selected leathers, reinforced stitching and wax-finished edges has a lifespan that depends largely on daily care: avoiding prolonged exposure to water and rotating use between straps are the two most effective practices. Quality artisan work on a fine leather is measured in years of daily wear, developing over time the patina that distinguishes a lived-in object from one that has simply been worn out.

The AP calibre 3132 fitted in this reference uses a double balance wheel, a technical solution that distributes inertia across two coupled oscillators, reducing the movement's sensitivity to wrist acceleration and shock. The skeletonised version exposes the full architecture of the movement, with finished bridges and surfaces treated according to the aesthetic standards of the Manufacture in Le Brassus. In a yellow gold watch, this visibility of the calibre creates a visual coherence between the warmth of the metal and the mechanical complexity beneath.