Swatch
Sistem 51 SUTN401— lug 20mm

The lug width of the SUTN401 is 20 millimetres. This dimension represents the internal space between the two lugs of the case, measured from edge to edge. It is compatible with any aftermarket strap fitted with standard 20-millimetre attachments.

The ideal strap depends on usage: alligator with vegetable tanning for formal settings, NATO or technical rubber for sport and daily wear. We recommend black or dark brown alligator for contrast with the luminous case, or burgundy red shell cordovan for aesthetic sophistication.

The SUTN401 features non-soldered lugs with standard spring bar attachments. Using a spring bar removal tool, press downward on the internal spring, extract the spring bar, remove the old strap and insert the new one by aligning it to the recesses. Reposition the spring bar and verify the locking mechanism.

Any strap with a 20-millimetre lug width is compatible. Avoid straps with deployante clasps thicker than 4 millimetres that could create tension on the plastic lugs. We recommend straps specifically tested for lightweight sport watches.

A quality leather strap (alligator, calf, shell cordovan) lasts 2–4 years with daily use and regular maintenance (drying, conditioning every 6 months). Longevity depends on environmental humidity, frequency of use and care. NATO and rubber straps last 5–8 years.