Rolex
Day-Date 36 128239-0021— lug 20mm
Rolex Day-Date 36 128239-0021: 20mm strap. Alligator, box calf, shell cordovan and rubber, cut and stitched in Milano. Choose your leather.
Artisanal Note
"This model requires a precise 20mm lug width to preserve the original sartorial balance."
Technical Specifications
Rolex 128239-0021The essential strap measurement.
Browse 20mm straps →128239-0021
Rolex caliber 3255 Hours, Minutes, Seconds | Date, Day | Chronometer
The Heritage
Compatible Straps
Selected for the 20mm lug width of the Day-Date 36
FAQ
What is the lug width of the Rolex Day-Date 36 128239-0021?
The lug width of the Day-Date 36 white gold reference 128239-0021 is 20 millimetres. This measurement denotes the horizontal distance between the two lugs (horns) of the case where the strap inserts. A compatible strap must have a thickness between 3.8 and 4.2 millimetres to sit without lateral play.
Which strap material is most suitable for the Day-Date 36 in white gold?
Alligator remains the traditional pairing with white gold, owing to its fine grain and patina that develops with natural elegance. Alternatively, vegetable-tanned calf leather offers tactile robustness and visible grain. For less formal wear, NATO fabric straps with leather keepers provide aesthetic versatility and daily practicality.
How do you change the strap on a Rolex Day-Date 36?
Strap replacement requires a dedicated tool (spring bar tool) or a thin-bladed screwdriver. Insert the tool into the lugs to depress the elastic pins and leverage the strap away. We recommend entrusting this task to a professional watchmaker or Casati Milano's service to avoid case damage.
Is a non-original aftermarket strap compatible with the 128239-0021?
Yes, any strap with a 20-millimetre lug width is mechanically compatible. However, construction quality, durability, and aesthetic coherence depend on the manufacturer. Casati Milano's handcrafted straps respect Rolex original parameters whilst offering bespoke personalisation and curated materials.
How long does a leather strap last on a daily-wear wristwatch?
The lifespan of a leather strap depends on the tanning process, usage, and maintenance. High-quality alligator or vegetable-tanned calf lasts between 4 and 7 years with daily wear. The patina that develops is part of its authenticity. Casati Milano straps include an 18-month warranty against manufacturing defects and are renewable upon request.
The next step
The right strap isn’t chosen. It is built, together.
From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.
Request an appointment →By appointment only · Milan
The atelier's website: casatimilano.com