Strap for Hydroconquest Automatic 41

The Longines HydroConquest L3.649.4.76.6 features a lug width of 21mm, measured between the internal attachment pins of the case. This measurement does not correspond to the international standard of 20mm, making it essential to verify compatibility before purchasing an aftermarket strap. Accurate measurement with a digital calliper ensures correct matching.

For a sports watch of this calibre, we recommend alligator leather in dark brown tones (cognac or cordovan) for elegant daily wear, or a technical FKM rubber or synthetic NATO strap if the watch will be used frequently in aquatic environments. The choice depends on balancing aesthetics with functionality: premium leather offers ageing and patina development, whilst rubber guarantees moisture resistance without compromise.

Strap replacement requires opening the case through the case back (this is not an integrated case model). Use a spring bar tool to extract the attachment pins from the lugs: this process is delicate and requires care to avoid damaging the case. We recommend having this operation performed by a specialised service centre or at Casati Milano atelier to ensure precision and case protection.

Yes, provided the strap is constructed specifically for a 21mm lug width. Aftermarket straps in artisanal leather, alligator, calf or technical rubber of quality standard are perfectly compatible and often represent an aesthetic upgrade compared to the original rubber strap. Always verify that the attachment pins are the same length as the case lugs to avoid instability during wear.

A natural leather strap (alligator, calf) has a lifespan ranging from 2 to 5 years with regular use, depending on frequency of wear, water exposure and tanning quality. Vegetable-tanned leather ages beautifully, developing patina and increasing in character. Casati Milano atelier offers an 18-month warranty on custom-made straps, and stitch repair remains possible beyond this period through professional re-stitching.