IWC
Pilot IW3713-05 (aka: IW371305)— lug 21mm

The lug width of the IWC Pilot IW3713-05 is 21 millimetres. This measurement is specific to this model and must be verified by measuring the space between the pins that attach the strap to the case lugs. It does not allow variation: a 20mm strap would appear undersized, whilst a 22mm strap will not fit physically into the lugs.

For the IW3713-05, we recommend Louisiana alligator for its fine grain and consistent pattern, or shell cordovan for those seeking visual substance that develops patina over years. Vegetable-tanned calf offers initial softness with predictable ageing. For daily use under high stress, reinforced fabric NATO is appropriate due to the breathability necessary in aviation contexts.

Remove the two lateral pins from the case lugs using a strap tool or similar device. Align the new strap (21mm lug width) and reinsert the pins carefully, ensuring they are fully seated. For models with fixed passants, verify that the new strap slides correctly through the passant during the operation without binding.

No, this is not recommended. The IW3713-05 requires precise 21mm lug width. Generic or non-specific straps will create lateral play, damage the lugs over time, and appear aesthetically unsuitable. We advise straps manufactured specifically for this exact lug width, where the lug design has been considered in the cutting process.

A quality leather strap, in vegetable tanning or shell cordovan, has an average lifespan of 3-5 years with daily use. Longevity depends on frequency of use, climate, and maintenance. Alligator leather is generally more resistant. Artisanal strap warranty is typically 18 months, but the leather continues functioning beyond: replacement is advised when the material begins to show micro-cracking or structural failure.