Strap for Sistem Boreal

The Swatch Sistem 51 YIS401G has a lug width of 20 millimetres. This measurement is standard for medium-proportioned wrists and is critical for selecting the correct strap. You can verify this by measuring the distance between the lug pins with a digital calliper: any strap sized for 20mm lug width will be compatible.

Your choice depends on intended use. For formal occasions, we recommend semi-gloss alligator or vegetable-tanned calf leather that develops patina over time. For daily sportive wear, nylon NATO straps offer versatility and quick-change practicality. For those seeking coherence with the Sistem51's technical philosophy, Fluoroelastomer rubber is waterproof and UV-resistant without aesthetic compromise.

The process is straightforward: position the watch on a soft surface and access the side lugs of the case (no visible screws, as the Sistem51 employs a monolithic structure). Using a pin extractor or specialised tool, gently remove the pin, slide off the old strap, and insert the new one. Ensure the replacement strap is precisely calibrated for 20mm lug width to avoid excessive play.

Any strap with 20mm lug width is compatible. Milano Straps offers a dedicated 20mm strap collection in artisanal leather, technical NATO, and performance rubber. Always verify the lug width is exactly 20mm before purchase to guarantee a perfect fit within the case.

A quality artisanal leather strap, crafted with vegetable tanning, typically lasts 3-5 years with moderate daily wear. Longevity depends on sun exposure, moisture and frequency of use. Vegetable-tanned calf develops natural patina, enhancing aesthetic appeal over time. Rubber is more robust against atmospheric agents and can last 5-7 years. Nylon NATO straps are virtually indestructible.