Strap for Defy El Primero 21 Ultrablue

The lug width is 23 millimetres. This measurement is specific to this model and represents a non-standard dimension in watchmaking, intentionally chosen by Zenith to maintain ideal visual proportions of the 44-millimetre case. Always verify with the retailer that the strap is constructed to precisely this specification before purchase.

The optimal choice depends on intended use and aesthetic preference. For formal wear: dark brown alligator or shell cordovan. For casual-sporty: vegetable-tanned calf or NATO. Alligator offers maximum contrast against the brushed titanium and conveys authority. Shell cordovan develops a unique patina over time. Calf allows broad chromatic personalisation. Select based on usage intent: formal lightness, casual versatility, or operational robustness.

Strap replacement requires removal of the spring bars—the small metal pins securing the strap to the case lugs. Use a dedicated tool to compress the internal pin mechanism, allowing the bar to slide from the lug. Install the new strap by ensuring the lugs align precisely with the case's internal passageways, then reinsert the spring bar. Verify stability and proper alignment. If uncertain, a professional watchmaker completes this in minutes.

Yes, provided it is constructed with precisely 23-millimetre lug width and the lugs are dimensioned for the Defy. Compatibility is not automatic: many aftermarket straps follow standard dimensions (20mm, 22mm) and will not fit correctly. Consult specialised artisans—such as Milano Straps—who construct bespoke straps ensuring precise fitment and stability.

Durability depends on material and usage frequency. Premium alligator withstands 3–4 years under moderate daily use. Shell cordovan, owing to fibre density, can exceed 5 years. Vegetable-tanned calf tends to wear more rapidly (2–3 years) yet develops a fascinating patina. Occasional use substantially extends longevity. Perspiration and humidity accelerate ageing; rotating between multiple straps significantly prolongs useful life.