Strap for Conquest 29.5 Quartz Moonphase Stainless Steel / MOP / Bracelet

The Longines Conquest L3.380.4.87.6 features a lug width of 15mm. This is a relatively uncommon measurement that requires straps specifically designed for this dimension. It is not compatible with the more common 14mm or 16mm standards. Measurement is performed using a digital calliper positioned between the inner edges of the lugs.

For this 29.50mm stainless steel timepiece, three primary options are recommended: alligator for maximum formal elegance, with characteristic texture and evolving patina; vegetable-tanned calf leather for a more understated but durable profile; NATO or technical textile straps to emphasise the sportive heritage of the Conquest line. Your choice depends on intended wear occasion and desired contrast level against the steel case.

Strap removal is accomplished by extracting the spring bars connecting the strap to the lugs using a specialised tool. Gently withdraw the bar to avoid scratching the case. Once the lugs are clear, insert the spring bar through the new strap and reposition into the lug until the retention click is felt. If inexperienced, we recommend having Casati Milano perform this operation on your first change.

Only straps specifically manufactured for 15mm lugs are compatible with this model. Standard widths (14mm, 16mm) will not fit correctly. Milanostraps.it curates a dedicated collection of 15mm straps in alligator, vegetable-tanned calf, shell cordovan and technical textiles, all customisable in length, initials and stitching thread colour.

Longevity depends on material composition and frequency of wear. A quality alligator strap, worn 3–4 times per week, maintains structural integrity for 4–6 years. Vegetable-tanned calf resists slightly longer (5–7 years) due to superior porosity resistance. Seasonal rotation and controlled ambient humidity substantially extend usable life. Casati Milano provides an 18-month warranty on all bespoke straps produced.