Strap for Hydroconquest Automatic 41

The lug width of the Longines HydroConquest L3.649.4.56.6 is 21mm. This measurement represents the distance between the two lugs (attachment points) on the watch case where the strap is secured. To verify this dimension, measure the distance between the lugs using a calliper when the watch is positioned naturally. All compatible straps must be 21mm wide to fit the case perfectly.

The optimal strap depends on your primary use case. For formal elegance, we recommend alligator or vegetable-tanned calf leather, which develops natural patina over time. For diving and sporty applications, an FKM rubber strap or high-density nylon NATO ensures waterproofness and durability. For maximum versatility, a dark brown or black calf strap pairs seamlessly with any occasion. At Casati Milano, you can personalise your choice with expert consultation and bespoke craftsmanship.

To change the strap, position the watch face-down on a soft cushion. Use a spring bar removal tool to gently press inward on the spring mechanism that secures each lug to the case terminal. Once loosened, the lug will slide out smoothly. Repeat for the opposite lug. To install the new strap, insert the lugs into their designated holes and push until you hear a distinct click, indicating secure closure. Always verify that both lugs are fully locked before wearing the watch.

Yes, the Longines HydroConquest L3.649.4.56.6 is fully compatible with aftermarket straps featuring a 21mm lug width. Bespoke artisanal straps, such as those crafted by Casati Milano, are available in premium leathers (alligator, calf, shell cordovan) or technical materials (FKM rubber, NATO nylon) with construction quality exceeding mass-market alternatives. The only requirement is accurate lug width measurement and confirmation that the strap is designed for 41mm cases.

A high-quality artisanal leather strap typically lasts 2–4 years with daily wear, provided it receives appropriate maintenance. Leather should be dried promptly after water exposure and conditioned with specialist balm every 3–4 months. Straps crafted from vegetable-tanned leather develop rich patina and may last beyond 5 years. If the strap experiences frequent immersion, durability reduces to 12–18 months; in such cases, opt for FKM rubber, which offers 3–5 years of wear without degradation. Casati Milano guarantees all bespoke straps for 18 months.