Strap for Hydroconquest GMT 41 Stainless Steel / Black / Rubber

The lug width of the Longines HydroConquest L3.790.4.56.9 is precisely 21 millimetres. This specification is unique to this model and represents an uncommon standard among diving watches. It is essential to verify this dimension before purchasing an aftermarket strap, as even slight variations (20mm or 22mm) would render the strap incompatible or unstable on the timepiece.

The ideal strap depends on intended usage. For sartorial elegance, vegetable-tanned alligator creates a pleasant contrast with the black ceramic bezel. If you frequently use the watch in water, vulcanised rubber or neoprene offer moisture resistance and rapid drying. A calf leather with 1.4-1.6mm thickness provides a balance between initial softness and longevity, developing a beautiful patina over time. NATO straps remain the most practical option for rapid strap changes.

The strap is changed by locating the two pins attached to the lugs of the case and connecting to the strap. Using a dedicated spring bar tool, press gently inward to release the pin from one side, then extract it completely. After removing the strap, repeat the operation on the opposite side. Installation of the new strap follows the same procedure in reverse: position the pin, insert it into the lug, and push until you hear a click confirming full engagement. It is important to verify that the pin is completely locked on both sides to prevent water loss.

Yes, any strap with a lug width of 21 millimetres is compatible with the L3.790.4.56.9, regardless of material chosen (alligator, calf, NATO, rubber). Compatibility is ensured by the standardisation of width: the case attachment pins correspond exactly to this dimension. It is advisable, however, to verify that the strap is not excessively thick (maximum 4.5-5mm) to avoid obstructing correct positioning within the case.

The lifespan of a leather strap depends on usage, frequency of water exposure, and tannage quality. A high-quality alligator or calf leather, if used moderately in water and subjected to regular maintenance (gentle cleaning and annual conditioning), has a longevity of 3-5 years. If the watch is frequently used in humid environments or chlorinated water, the lifespan reduces to 1-2 years. Primary use in water should rely on technical straps in rubber or neoprene, which maintain their elastic and resistant properties for 5-7 years with minimal maintenance.