Strap for El Primero Chronomaster Open Stainless Steel / Black / Rubber

The lug width of the Zenith El Primero 03.2040.4061/21.R576 is 20 millimetres. This measurement refers to the distance between the spring bar attachment points and is essential for selecting compatible straps. To verify it, position a ruler under the upper and lower attachment points: the distance between the two anchor points must be exactly 20 mm.

The Zenith El Primero 03.2040.4061/21.R576, being a sporty-elegant chronograph, pairs beautifully with black alligator (for formal occasions), dark brown calf leather (for natural patina over time), grey or blue military NATO (for extreme practicality), or dark grey FKM rubber (for a modern aesthetic and water resistance). The choice depends on the context of use: formal, daily, or sporting.

To change the strap, you need to remove the spring bars from the case lugs. Use a dedicated tool (spring bar tool) to press the ends of the spring bar inward, creating enough space to remove the old strap. Then insert the new strap by aligning the two attachment points perfectly with the spring bars, ensuring they click into position. If you do not own the tool, contact an authorised Zenith service centre or the Casati Milano atelier.

Yes, provided the lug width is exactly 20 millimetres. High-quality artisanal aftermarket straps, such as those from Milano Straps, are completely compatible and often offer greater flexibility in material choice and customisation options compared to the original Zenith alternatives. Always ensure that the buckle or closure system is appropriate for your wearing preferences.

The durability of a leather strap depends on the intensity of use and the type of material. A high-quality alligator or calf leather, worn daily, typically lasts 3–5 years before needing replacement. If worn occasionally, it can exceed 7–8 years. The natural ageing of leather, developing patina and micro-cracks, does not compromise functionality but signals the time for a change. FKM rubber straps, on the other hand, maintain their technical characteristics unchanged for 5–7 years.