Longines
HydroConquest L3.780.4.56.6— lug 19mm

The lug width is 19mm, a specific measurement for this reference that does not correspond to standard industrial sizes such as 18mm or 20mm. Measuring the lug correctly is essential when purchasing compatible straps: position a digital calliper between the inner shoulders of both lugs, keeping the axis parallel to the case diameter. This measurement ensures harmonious proportions on the 39mm case.

The choice depends on your intended use: for diving and aquatic activities, alligator in vegetable tanning or shell cordovan ensure moisture resistance and develop patina over time. For formal daily wear, Tuscan calf with stainless steel deployante offers elegant functionality. For intensive sports and diving, vulcanised rubber is unbeatable in durability and zero maintenance. Ideal colours include chocolate brown, deep black, or dark blue, which enhance the blue dial and ceramic bezel without competing visually.

The strap is attached to the case via two removable horizontal pins positioned between the lugs. Use a spring bar tool to gently press the pin and extract it from its seat. Once both ends of the old strap are free, slide the new strap under the lugs and reinsert the pins into their respective seats, using the tool to lever until they click into place. Verify that both pins are fully seated before wearing the watch.

Absolutely. A bespoke 19mm strap crafted from premium leather with stainless steel deployante significantly elevates the tactile and aesthetic experience of the watch. The quality of the tanning, the finishing of the lug edges, the choice of thread all contribute to transforming the HydroConquest into a personal instrument. Casati Milano and specialised suppliers offer customisable options in size, colour and finish, ensuring precise compatibility.

Durability depends on the tanning method, use intensity and maintenance practices. An alligator or shell cordovan strap, both in vegetable tanning, lasts 3–5 years if exposed to frequent moisture (e.g. regular diving), up to 7–10 years if worn daily in a dry environment. Tuscan calf, more sensitive to moisture, has similar lifespan but requires periodic air-drying. Vulcanised rubber, lacking organic properties, lasts 5–8 years before losing elasticity. Proper care—swift drying after water contact, periodic conditioning with vegetable cream—substantially extends strap life.