Strap for Hydroconquest Automatic 39

The lug width (ansa measure) of the Longines HydroConquest L3.648.4.96.6 is 19mm. This measurement refers to the internal distance between the watch lugs and determines strap compatibility. To verify, measure with a digital calliper the internal space between the two opposite lugs, perpendicular to the caseback surface.

For the Longines HydroConquest L3.648.4.96.6, we recommend genuine alligator for elegance and water resistance, English calf for natural patina development over time, or FKM rubber if the watch will be regularly immersed. Your choice depends on intended use and aesthetic preference: alligator emphasises the sophistication of the brushed steel case, rubber amplifies the functional character of the diver.

Strap replacement requires removal of the spring bars. Position the watch on a soft pad with the lugs facing upward. Use a spring bar tool to gently push the lug bar pin towards the centre of the case; the pin will retract allowing extraction of the worn strap. Insert the new strap by aligning the holes with the lugs and press the pin until it clicks. Verify both ends are correctly secured before wearing the watch.

Yes, the Longines HydroConquest L3.648.4.96.6 accepts any aftermarket strap with 19mm lug width, provided the lengths are compatible with your wrists (generally between 18-24cm total). Bespoke leather straps from milanostraps.it are available in leather, rubber and textiles, all certified for this lug width and completed with stainless steel or titanium deployante buckles.

The lifespan of a leather strap depends on material and usage. Genuine alligator resists 3-5 years with moderate wear and occasional water contact. English calf lasts 2-4 years before replacement becomes necessary, but develops an appreciated patina for those who value ageing. If the watch is worn daily in humid environments, FKM rubber is advised as it resists indefinitely. Casati Milano offers an 18-month guarantee on all bespoke straps.