IWC
Pilot IW3713-42 (aka: IW371342)— lug 21mm

The lug width is 21 millimetres. This measurement is specific to this model and requires straps compatible with exactly 21mm. Any miscalculation compromises both the aesthetics and the functional integration between case and strap.

There is no universal absolute choice; it depends on intended use. For elegance and natural ageing: vegetable-tanned calf in dark brown. For luxury without compromise: alligator in black or cognac. For contemporary military aviator: ballistic nylon NATO in grey. For sweaty wrist or work environment: grey or black FKM rubber.

Strap replacement requires a spring bar tool. Insert the tool into the slot beneath each lug, push inward to release the spring bar, gently extract the old strap with horizontal motion, then align and insert the new strap. Alternatively, consult a professional watchmaker to avoid case scratching.

Yes, provided they respect the 21mm lug width and feature standard removable spring bars (minimum 18mm length). Artisanal leather, rubber, or textile straps compatible with this measurement mount identically to original IWC pieces and offer greater aesthetic personalisation.

A quality leather strap, with vegetable tanning, resists 3–5 years with regular maintenance (quarterly cleaning, drying after moisture exposure). Alligator leather lasts 2–3 years before visible wear appears. Longevity depends on frequency of wear, direct sunlight exposure, and ambient humidity. Casati Milano guarantees 18 months on bespoke straps.