IWC
Pilot IW3713-08 (aka: IW371308)— lug 21mm

The lug width of the IWC Pilot IW3713-08 is 21 mm. This is an unusual size, not standardised like the common 20 mm or 22 mm widths. To verify accurately, measure the perpendicular distance between the two spring bars located at the sides of the case. This precision is essential to ensure a proper strap fit.

For the Pilot IW3713-08, we recommend materials that respect the austere aviatic character of the watch: alligator with regular grain in mud brown or black tones, vegetable-tanned calf leather that ages visibly over time, or shell cordovan for those seeking greater elegance. For sport applications, a rubber or NATO strap preserves the original aviatic functionality. At milanostraps.it, you will find 21 mm straps customisable in colour, initials, and stitching thread.

The Pilot IW3713-08 uses standard spring bars. To change the strap, use a spring bar tool or fine ballpoint pen: insert the tool into one of the small holes at the ends of the bar, press gently to compress the internal spring, and remove the lug from the case. Work carefully to avoid scratching the steel case. Repeat on the other side, then insert the new strap by seating the spring bars in their sockets.

Yes, any strap with a 21 mm lug width is mechanically compatible. However, we recommend choosing artisanal straps that respect the proportions and aviatic character of the Pilot. Generic commercial straps often feature poor finishing or incongruous thicknesses. The Casati Milano atelier and straps curated on milanostraps.it guarantee construction quality, noble leather, and sartorial details.

Durability depends on leather quality and usage patterns. A quality alligator or shell cordovan strap typically lasts 5–7 years with daily wear. Vegetable-tanned calf leather has similar longevity, but patina becomes visible within 6–12 months. Rubber lasts approximately 3–4 years before degradation. Ageing is not a flaw but character: Casati Milano straps maintain 18-month warranty on materials and stitching, covering any manufacturing defects.