Strap for Master Ultra Thin Réserve de Marche Stainless Steel / Silver / Alligator

The Q1378421 features a <a href="/pages/termine-glossario/misura-ansa">21mm lug width</a>, a dimension that characterises the Master Ultra Thin models in their more compact case configuration. This size represents the standard for this watch family and allows access to a wide selection of artisanal straps, from traditional materials to modern options such as vulcanised rubber.

For the Q1378421, the ideal choice falls upon straps in <a href="/pages/termine-glossario/alligatore">alligator</a> or premium calf leather, which enhance the minimalist character of the case. Mississippi alligator offers a regular, discreet texture that emphasises the formal sobriety of the timepiece, whilst calf leather with <a href="/pages/termine-glossario/concia-vegetale">vegetable tanning</a> imparts warmth and develops patina over time. For a sportier interpretation, a NATO or rubber strap maintains the elegant profile without weighing down the wrist.

Changing the strap on the Q1378421 requires a specific tool to extract the pins from the lugs. Place the watch on a soft cloth, locate the two lateral pins securing the strap to the 21mm lugs, apply the tool with steady pressure and extract the pin in the direction opposite to the case. Install the new strap by reversing the procedure. If you prefer to avoid any risk, the Casati Milano atelier offers a professional strap-change service with personalised consultation.

All artisanal straps with a <a href="/pages/termine-glossario/misura-ansa">21mm lug width</a> are compatible with the Q1378421. The collection of <a href="https://milanostraps.it/collections/cinturini-orologi-per-misura-ansa-21mm">21mm straps</a> includes options in alligator, <a href="/pages/termine-glossario/shell-cordovan">shell cordovan</a>, calf, canvas and rubber. Before purchase, we recommend verifying the buckle or <a href="/pages/termine-glossario/deployante">deployant clasp</a> width, which must correspond to the lug width.

A premium leather strap paired with the Q1378421, subject to regular use and ordinary maintenance, retains structural integrity for 4-6 years. The natural fibres of leather, particularly calf or alligator, develop a characteristic patina that increases aesthetic appeal over time. Factors such as humidity, direct sun exposure and frequency of wear influence longevity. A strap treated with natural wax and stored in a dry environment ages gracefully.