Rolex
Day-Date 36 118238-0108— lug 20mm

The lug width of the Rolex Day-Date 36 reference 118238-0108 is precisely 20 millimetres. This measurement represents the distance between the two lugs (or terminals) where the strap attaches to the case. It is critical to verify this measurement before purchasing any aftermarket strap, as even a 1-millimetre discrepancy will result in misalignment or instability.

For the Day-Date 36 in yellow gold (reference 118238-0108), virgin alligator in cognac colour remains the classical choice that complements the precious metal. Shell cordovan in burgundy-brown offers a more refined alternative, with a patina that develops naturally over time. For contemporary craftsmanship, round-grained calf in vegetable tanning guarantees longevity exceeding five years and beauty that improves with age. Selection depends on context: alligator for formal occasions, calf for elegant daily wear.

Changing the Day-Date 36 strap requires two tools: a spring bar removal tool and a steady hand. Position the watch on a soft cloth with the lugs visible. Insert the tool into the small aperture beneath one lug and push towards the opposite side; the pin will spring out. Repeat for the other lug. Subsequently, position the new strap terminals into the open spaces and reinsert the pins until they click into place. Alternatively, this service can be performed by any authorised watchmaker or through Casati Milano by appointment.

Any strap with a 20-millimetre lug width is compatible with the Day-Date 36. Superior aesthetic results are achieved with premium leathers: African or American alligator, shell cordovan, vegetable or vegetable-synthetic tanned calf. Avoid straps that are excessively rigid or thick, as these may alter the watch's proportions. Milano Straps curates a selection of 20mm straps that respect the quality standards of luxury horology.

The lifespan of a leather strap depends on material and usage. High-quality alligator guarantees 3-4 years of regular wear before showing fatigue. Shell cordovan, owing to its naturally rigid structure, can endure 5-7 years. Calf leather in authentic vegetable tanning easily achieves 5-6 years whilst beauty increases with patina development. Humidity, perspiration, and direct sunlight accelerate ageing: to extend lifespan, clean the strap monthly with a slightly damp cloth and store in a dry environment.