Strap for Heritage Legend Diver 39 Stainless Steel / Blue / NATO

The lug width of the Longines Legend Diver L3.764.4.90.2 is 20 millimetres. This measurement represents the internal distance between the two spring bars of the case where the strap is attached. It is essential to verify this dimension before purchasing an aftermarket strap to ensure perfect compatibility and prevent damage to the spring bar pins.

The ideal strap depends on your usage and aesthetic preference. For formal elegance, we recommend alligator or vegetable-tanned shell cordovan, which age beautifully. For everyday versatility, vegetable-tanned calf leather is excellent: it breathes, develops natural patina, and maintains the sport-elegant character. For a more military aesthetic, a robust nylon NATO strap emphasises the model's diving heritage.

The strap is changed by removing the two spring bars (pins) that connect the strap to the case lugs. Use a dedicated spring bar tool to compress the pin on one side, extract it from its seat, then slide off the old strap. Insert the new 20mm strap, reinsert the pin into the seat and release until it clicks. Verify that both sides are properly fixed before wearing the watch.

Yes, you can use certified quality aftermarket straps provided they respect the 20mm lug width and aesthetic proportions of the case. Artisanal leather straps in fine materials (alligator, shell cordovan, calf) often offer superior craftsmanship and customisation compared to OEM straps. Always verify the lug width compatibility before purchase.

Longevity depends on frequency of wear, ambient humidity, and material type. Quality vegetable-tanned calf lasts approximately 2–4 years of daily wear. Alligator and shell cordovan, being more robust, can last 4–6 years. Vulcanised rubber resists 3–5 years if exposed to chlorine or intense sunlight. The natural ageing of leather is desirable: patina and creasing add character. Replacement remains the simplest and most reversible way to refresh your watch's aesthetic.