Strap for Symphonette M Diamond / Black

The lug width of the Longines Symphonette L2.305.0.57.0 is 9mm. This measurement refers to the distance between the two lugs of the case where the strap is inserted. It is a non-standard dimension and requires straps specifically manufactured for this geometry. Measuring the lug width correctly means placing a ruler horizontally between the lugs, excluding the metal part of the springs themselves.

For the Longines Symphonette L2.305.0.57.0, natural alligator is the most elegant choice, with uniform grain that enhances the refined geometry of the case. Vegetable-tanned calf leather offers versatility and soft hand, ideal for daily transitions. Shell cordovan, with its unique chromatic depth, represents a long-term investment. Technical materials such as NATO or fabric can work but require customisation due to the non-standard 9mm lug width.

To change the strap, obtain a spring bar tool or consult a professional watchmaker. Position the tool in the small hole of the spiral spring supporting the lug bar, apply gentle pressure to release the bar and remove it. Slide out the old strap and insert the new one, ensuring the width is exactly 9mm and that the lug bar re-inserts correctly into the lugs. Avoid excessive force on the internal springs.

Yes, the Longines Symphonette L2.305.0.57.0 is compatible with any 9mm strap, regardless of brand. However, since 9mm is a non-standard and uncommon size in the aftermarket, pre-made options are limited. To maximise aesthetic and build quality, it is advisable to rely on specialists who create bespoke straps for this specific lug width, such as Milano Straps.

The lifespan of a leather strap depends on material, usage and maintenance. High-quality alligator or calf, worn daily with care, typically lasts 2–3 years before replacement. Shell cordovan, being more robust, can reach 4–5 years or longer. Factors such as sun exposure, humidity and wrist pressure accelerate ageing. Casati Milano atelier provides an 18-month warranty on bespoke straps, covering manufacturing defects and guaranteeing maintenance interventions.