Strap for HydroConquest 39 Automatic Stainless Steel / Blue / Bracelet / Star Navigation

The lug width of the Longines HydroConquest L3.675.4.96.6 is 19 mm. This specific dimension represents an intermediate standard between contemporary 18 mm and vintage 20 mm lugs, inherited from historical HydroConquest versions and maintained in modern editions. To verify compatibility, measure the distance between the inner shoulders of the case terminals.

Strap selection depends on your intended use. For formal elegance and visible aging, we recommend alligator or vegetable-tanned calf leather with natural patina development. For intensive water activities, shell cordovan offers superior moisture resistance. NATO fabric straps provide versatility and practicality, whilst rubber remains the optimal solution for scheduled diving expeditions.

Strap replacement requires a specialist tool called a spring bar tool or a watchmaker's hammer. Position the watch on a protective cushion, identify the thin pins at the case terminals, insert the tool into the small hole beneath the pin, and apply gentle, constant pressure until the pin disengages from its seats. Replace the strap by aligning the new pins and reinserting the original pins using the reverse procedure.

All straps with 19 mm lug width are compatible with your HydroConquest. On milanostraps.it you will find a selection of straps in alligator, calf, shell cordovan, NATO, and rubber, all available in 19 mm sizing and customisable in length, initials, and thread colour. The Casati Milano atelier also offers bespoke solutions with personal consultation.

A quality leather strap, when properly maintained, lasts between 3 and 7 years depending on usage and exposure to water and moisture. A HydroConquest, being a sports diving watch, exposes the strap to greater stress. Vegetable-tanned leather ages visibly and gracefully, developing a patina that enhances aesthetic appeal. We recommend alternating straps to reduce stress and extend overall durability, and keeping the leather dry following prolonged contact with freshwater or saltwater.