Strap for Sistem Navy

The lug width of the SUTN400 is 20 millimetres. This measurement corresponds to the distance between the two attachment pins on the case and determines compatibility with any strap. To verify it, position a digital calliper on the case perpendicular to the lugs: the resulting value must be exactly 20mm.

The most suitable strap depends on intended use. For elegant everyday wear, we recommend vegetable-tanned calf leather in cognac or pearl grey tones, which balances tastefully against the plastic case. For sport and guaranteed water resistance, a black satin FKM rubber strap eliminates any water anxiety. A woven NATO strap offers colour versatility and rapid changes, ideal for those who alternate looks without additional investment.

The SUTN400 uses standard spring bar lugs. Position the watch on a soft surface (cloth), locate the small lateral holes on the lugs, insert a spring bar tool into one of the holes to compress the internal spring, pull the old strap outward and remove it. Repeat the operation on the opposite side. Insert the new strap by aligning the holes to the lugs, press the tool to compress and let it snap into place.

Yes, but we advise caution. Any 20mm strap is theoretically compatible, but construction quality determines durability. Milano Straps provides carefully selected artisanal straps, verified for fit and made with leather or structured materials, guaranteeing longevity beyond 3-5 years of daily use. Generic commercial straps often feature fragile stitching and uneven finishing.

A quality artisanal leather strap, with vegetable tanning and reinforced stitching, typically lasts 4-6 years with daily use and ordinary maintenance (periodic cleaning, conditioning every 12 months). Vegetable-tanned calf leather develops a desirable patina that improves aesthetics over time. Factors that accelerate wear: constant moisture exposure, lack of post-water drying, repeated bending at the same point. Casati Milano offers lug replacement and leather regeneration services to extend useful life.