Rolex
Datejust 31 278240-0004— lug 16mm

The lug width of the Rolex Datejust 31 278240-0004 is 16 millimetres. This measurement represents the internal distance between the two metal terminals of the case and is essential for purchasing a compatible strap. When measuring with a digital calliper, ensure zero tolerance to guarantee secure attachment and water resistance.

Alligator is the traditional choice for pure elegance, with natural and regular grain. Vegetable-tanned calf develops patina over time. Shell cordovan offers superior strength and compactness. Rubber straps guarantee daily practicality without compromise. Choice depends on use: formal wear for alligator, daily versatility for calf, sporty for rubber.

Strap replacement requires a specific tool to extract the spring bar from the terminals of the case. Position the watch on a soft surface, locate the small opening on the terminal, insert the tool to compress the spring and retract the bar. Repeat on the other side. Mount the new strap by reversing the procedure, ensuring the bar clicks securely into position. If inexperienced, consult an authorised Rolex centre or qualified watchmaker.

Rolex does not invalidate international warranty coverage for strap changes with certified aftermarket products. However, if anomalies result from incorrect installation, Rolex may exclude coverage for that specific defect. We recommend documenting the installation and using straps from verified artisans, such as Casati Milano, which guarantee compatibility and quality.

A quality leather strap with vegetable tanning typically lasts 18–24 months with daily use and routine maintenance. Longevity depends on humidity exposure, climate and frequency of wear. Dense leathers such as shell cordovan exceed three years. A rubber strap maintains structural integrity for 3–4 years. To extend lifespan, avoid prolonged water exposure and occasionally apply conditioning treatments to natural leathers.