Strap for Portofino Chronograph 150 Years Stainless Steel / White

The lug width of the IWC Portofino IW3910-24 is precisely 20mm. This measurement represents the distance between the two spring bars that attach the strap to the case and is essential for selecting a compatible replacement strap. A different lug width will not fit physically and will compromise the proportional aesthetics of the watch. Always verify the distance between the lugs before purchasing a replacement strap.

For this stainless steel automatic chronograph, we recommend a dark brown alligator with matte finishing to emphasise its professional character, or shell cordovan for those who appreciate a rare leather and a patina that evolves over time. Vegetable-tanned calf leather offers versatility between formal and informal contexts. For sporting use, a nylon NATO with leather keeper combines durability and elegance. The choice depends on daily wear and personal colour palette.

Strap replacement requires a specific tool called a spring bar tool: a small mechanism that allows you to gently push the spring bar out of the case without damaging it. Position the watch face down, locate the spring bar (small metal cylinder on the side), use the tool to push it out of the case hole, then remove the old strap. Insert the new strap by aligning the holes with the lugs and reposition the spring bar with gentle pressure. If not confident, consulting a professional watchmaker remains the safest option.

Yes, high-quality aftermarket straps are available online ready for immediate shipping, crafted from fine leather (alligator, shell cordovan, vegetable-tanned calf) and customisable in size, initials and stitching type. However, for a complete bespoke experience, the Casati Milano atelier creates custom straps with personal selection of leathers, photographic updates via WhatsApp and an 18-month warranty. The difference lies in artisanal consultation and prolonged durability.

A fine leather strap, if crafted with vegetable tanning or shell cordovan and cared for properly, has an average lifespan of between 4 and 7 years, depending on daily use, environmental humidity and maintenance. Rotating between multiple straps extends their life. Premium European alligator maintains structural integrity beyond 5 years; shell cordovan, thanks to the density of the leather, can exceed 7 years. Regular maintenance (gentle cleaning, treatment with natural balms) and alternating between leather and rubber straps maximises longevity.