Strap for Day-Date 36 White Gold Diamonds / President Diamond / Silver

The lug width (ansa width) of the Day-Date 36 reference 118389-0109 is 20 millimetres. This measurement is standard across the Day-Date 36 family and represents the space between the two case lugs where the strap is fitted. Rolex's manufacturing tolerance is approximately ±0.3mm per batch, meaning values between 19.8 and 20.2mm are considered conforming. To verify this precisely, use a digital calliper positioned perpendicularly to the lugs.

For the Day-Date 36 in white gold, the ideal strap is alligator leather in dark tones (taupe, graphite grey) or shell cordovan with vegetable tanning. These choices maintain the formal elegance of the gold case without creating excessive colour contrast. For summer wear, golden or white calf leather offers an equally refined option. Synthetic materials are discouraged: the gold case requires a tangible counterpart of perceptible quality.

Changing the Day-Date 36 strap requires specific tools: a spring bar removal tool (also called strap changer) and a small non-magnetic hammer. Position the watch securely on a soft surface. Insert the bifurcated tip of the spring bar tool beneath the lug and push gently to compress the retaining spring, then slide the strap downwards. Repeat on the opposite side. Installing the new strap follows the reverse procedure: align the strap's hole with the lug, compress the spring, and slide until seated. If inexperienced, we recommend having the operation performed at Casati Milano or an authorised Rolex service centre.

Yes, any quality artisanal strap manufactured to 20mm lug width is compatible with the Day-Date 36 reference 118389-0109. Our Milano Straps are crafted bespoke at the Casati Milano atelier with manufacturing tolerances that guarantee perfect fit into the Rolex case. The quality of leather and the finishing of the keepers distinguish our offering from generic straps: each band is hand-finished individually, undergoes artisanal quality controls, and benefits from an 18-month guarantee against manufacturing defects.

The lifespan of a leather strap depends on material, treatment, and usage. Quality alligator leather with vegetable tanning can last 5-7 years with daily wear, with the patina becoming a visible archive of use history. Vegetable-tanned shell cordovan offers similar performance with slightly superior durability thanks to fibre density. Calf leather typically lasts 3-5 years. Critical factors include prolonged exposure to moisture, perspiration, and direct heat: rotating between multiple straps considerably extends each strap's life. Casati Milano straps benefit from an 18-month guarantee against manufacturing defects and can be refurbished or replaced at the atelier.