Strap for Defy El Primero 21 Patrick Mouratoglou

The Zenith Defy 10.9000.9004/M99.R939 features a 23mm lug width. This is the critical measurement to consider when purchasing a compatible strap. To verify the width accurately, remove the current strap with the watch case open and measure the internal distance between the two attachment pins at their maximum aperture.

Alligator leather represents the most refined choice, with a consistent grain pattern that creates a compelling dialogue with the minimalist geometry of the carbon fibre case. Shell cordovan is ideal if you seek natural patina development and a deep burgundy colour. Calf leather offers an organic, versatile grain. For sportier contexts, technical rubber and NATO straps provide practicality and durability.

To change the strap, obtain a spring bar tool (a specialised implement with two pointed ends). Insert one tip into the lateral hole of the lug slot, pushing the pin downward. Once the first side is released, repeat from the opposite side. Extract the strap and reverse the procedure with the new strap, ensuring the pins enter the 23mm slot correctly.

Yes. Milano Straps offers a curated collection of artisanal 23mm straps compatible with your Defy, customisable in leather type, length, initials and stitching thread. Each strap is crafted to guarantee precise tolerances and rigorous finishing. The Casati Milano atelier also creates bespoke straps with personal leather selection and an 18-month warranty.

Longevity depends on frequency of wear and leather type. High-quality artisanal alligator or shell cordovan lasts between 5 and 10 years with moderate daily use. Calf leather has comparable lifespan but develops patina more rapidly. NATO or rubber straps typically require replacement after 3-5 years. Proper storage—away from excessive humidity and heat sources—significantly extends strap life.