Rolex
Day-Date 36 118348-0090— lug 20mm

The Rolex Day-Date 36 reference 118348-0090 features a lug width of exactly 20 millimetres. This measurement represents the horizontal distance between the two lugs (pimples) that hold the watchband's spring bars. Verifying this dimension when purchasing an aftermarket strap is critical, as an incorrect width risks premature wear on the case lugs and compromises overall aesthetic stability.

For an 18-carat yellow gold case, alligator leather in cognac or medium brown tones represents the premier choice: fine grain, natural patina development over time, and visual compatibility with the precious metal. Equally valid alternatives include vegetable-tanned calf leather (thicker texture, pronounced ageing) or shell cordovan (crystalline density, intrinsic lustre). Selection depends on usage context: alligator for formal occasions, vegetable-tanned calf for sophisticated daily wear, cordovan for limited collections.

Replacing the Day-Date 36 strap requires removal of two horizontal spring bars using a dedicated spring bar tool. Position the watch with the strap facing upward, gently push the tool beneath the spring bar to release the internal spring, then extract the bar from the case lug. Repeat on the opposite side. Next, insert the new strap by aligning its holes with the lugs and press until you hear the click of engagement. If inexperienced, consult an official Rolex service centre or specialised watchmaker to prevent case scratching.

A bespoke strap from a specialised atelier (such as Casati Milano) typically includes a warranty against manufacturing defects: normally 18 months on stitching, spring bar tension and buckle or deployant stability. The warranty does not cover natural leather ageing, staining from environmental exposure, or damage from misuse. It is essential to verify warranty terms prior to purchase and retain proof of sale. An original Rolex strap through the official service offers extended warranties but at significantly higher cost.

A quality alligator strap, with appropriate maintenance (regular cleaning, drying after moisture exposure), guarantees longevity of 5–8 years with moderate daily use. Vegetable-tanned calf leather, more durable but with more open fibre structure, maintains structural integrity for 3–6 years. Shell cordovan, due to its molecular density, can reach 10–15 years. Actual lifespan depends on usage frequency, climate, perspiration and water exposure. A strap exposed to direct sunlight, heat and prolonged humidity visibly degrades within 2–3 years. Store in a cool, dry environment; avoid perfumes and chemical solvents.