Longines · HydroConquest

Strap for Hydroconquest 41 Quartz Chronograph Stainless Steel / Black / Bracelet

Takes 21 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.

Lug width21 mm
Case diameter41 mm
ReferenceL3.743.4.56.6 (aka: L37434566)
FamilyHydroConquest
MovementLongines caliber L440.2 Hours, Minutes, Small Seconds | Date | Chronograph, Rattrapante
CaseStainless Steel

Spring bar

Swiss Standard universal spring bars

The right category for this model · 316L steel, all lug widths 13–26 mm

Straps for the HydroConquest L3.743.4.56.6 (aka: L37434566)

Selected for the 21 mm lug width · workshop selection

All 21 mm straps →

The HydroConquest L3.743.4.56.6 (aka: L37434566), seen from the bench

The HydroConquest represents Longines' sports dive collection, characterized by high water resistance. The model is powered by the L440.2 caliber with hour, minute, small seconds, date, and split-seconds chronograph functions. The lugs measure 21mm in width.

Frequently asked questions

What is the lug width of the Longines HydroConquest L3.743.4.56.6?

The HydroConquest L3.743.4.56.6 features a lug width of 21 millimetres. This is a precise standard: straps measuring 20mm or 22mm are not compatible. For accurate measurement, use a digital calliper, positioning the tips inside the lugs where the strap sits.

Which strap is best suited for the Longines HydroConquest L3.743.4.56.6?

For this modern diver, we recommend: black or brown alligator for business contexts; vegetable-tanned leather for versatility and moisture resistance; vulcanised rubber for intensive nautical use; fabric NATO for practicality and ease of change. Your choice depends on intended usage: refined aesthetics or extreme functionality.

How do you change the strap on the Longines HydroConquest L3.743.4.56.6?

Use a spring bar tool to extract the two spring-loaded pins securing the strap to the lugs. Position the tool in the small lateral notch of the pin, gently push downward to compress the internal spring, then withdraw the pin. For installation, reverse the procedure, ensuring the pin is fully seated.

What is the best aftermarket 21mm strap alternative for this watch?

On milanostraps.it you will find aftermarket straps in alligator, leather and rubber, all manufactured with 21mm lugs. We recommend keeping at least one spare strap, particularly if you wear the watch frequently in humid environments. Optionally, the Casati Milano atelier produces custom-made straps with selected leathers and personalised finishes.

How long does a leather strap last on the Longines HydroConquest L3.743.4.56.6?

A high-quality artisanal leather strap (alligator or vegetable-tanned leather) typically lasts 3-5 years with regular use. Lifespan depends on climate conditions (humidity accelerates wear), frequency of wear and maintenance practices. Rubber straps offer superior longevity (7-10 years), whilst fabric NATO straps last 2-3 years before visible wear develops.

The next step

The right strap isn't chosen. It is built, together.

From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.

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Casati Milano · Via XX Settembre 15, Milan · by appointment only