Strap for Master Collection 40 Date Stainless Steel / Bucherer Blue

The lug width of the Longines Master Collection L2.793.4.99.2 is 21mm. This unusual measurement represents the perfect geometric compromise for the proportions of the 40mm case. To verify it, use a digital calliper, positioning it on the inner shoulder of the lug — the surface that rests on the case spring bar — perpendicular to the bar itself.

Nile crocodile leather is the ideal choice: its natural grain pattern dialogues extraordinarily well with the austere elegance of the case. Alternatively, box calf with vegetable tanning offers a patina that evolves magnificently over time. Quality canvas NATO straps work superbly for sports and informal contexts. Rubber and silicone are discouraged for this classically-minded line.

Obtain a spring bar tool — a flat-leveraged instrument — and position it beneath the spring bar (the small metal shaft holding the strap in place). Press gently upward to release tension, then slide out the used strap. Repeat on the opposite lug. Insert the new strap by threading the spring bar through its slots until you hear a click of engagement. If uncertain, consult a professional watchmaker.

Yes, any strap with a 21mm lug width is physically compatible. However, verify that the strap lugs — the holes through which the spring bar passes — have an internal width of at least 2.4mm to accommodate the bar comfortably. Straps with overly narrow lugs may present installation difficulties. All MilanoStraps 21mm straps comply with this standard.

Longevity varies according to material and wear pattern. Premium crocodile leather, worn regularly (5–6 days weekly), retains appearance and functionality for 4–6 years before aesthetic maintenance becomes advisable (finishing work). Vegetable-tanned calf, owing to its porosity, tends to last slightly shorter — 3–4 years — yet develops a visually increasingly compelling patina. The MilanoStraps warranty covers 18 months against manufacturing defects.