Strap for Pilot's Watch Spitfire Double Chronograph Stainless Steel / Black / English / Strap

The lug width of the IWC Pilot IW3713-33 measures 21 millimetres. This dimension corresponds to the distance between the two metal lugs that protrude from the case at the vertical extremities (12 o'clock and 6 o'clock). The measurement tolerance is strict: the value must oscillate between 20.9 and 21.1 millimetres to ensure perfect ergonomic strap compatibility.

The best strap for the IW3713-33 depends on the intended use. For formal and professional contexts, we recommend alligator leather with vegetable tanning or English calfskin: both preserve the sober aesthetic of the Pilot. For operational use, a NATO strap in 1000D nylon offers reliability and versatility. The selection should consider colour coordination with the black dial: natural brown alligator or burgundy calfskin are refined and durable choices.

Changing the strap on the IW3713-33 requires a spring bar tool – a specialised instrument available in watch maintenance kits. Position the tool beneath the metal lug of the strap, apply outward pressure to compress the internal springs, and extract the spring bar. Repeat on the opposite side. The reverse operation installs the new strap. If you are inexperienced, it is advisable to consult a qualified watchmaker to avoid damage to the case.

Yes, many aftermarket straps are compatible with the IW3713-33, provided they respect the 21-millimetre lug width. milanostraps.it offers a dedicated collection of handcrafted 21mm straps that can be personalised in materials, finishes and colours. The Casati Milano atelier also creates bespoke straps with personalised consultation and an 18-month warranty, allowing you to select leathers, textures and constructive details according to individual preferences.

The lifespan of a leather strap varies according to material and usage. An alligator strap with vegetable tanning, used daily, maintains structural integrity for 5–7 years; English calfskin achieves 4–5 years. Shell cordovan, due to its fibre density, can exceed 8 years. Visible wear – thinning, creasing, discolouration – is natural and characteristic of authentic leather. Proper maintenance (monthly cleaning, half-yearly conditioning) significantly extends longevity. The Casati Milano atelier provides an 18-month warranty on custom-made straps.