Strap for Speedmaster Professional Moonwatch 3861 Stainless Steel - Sedna Gold / Pink

The reference 310.20.42.50.99.001 is fitted with a 20mm lug width. This measurement is critical for strap compatibility: a different diameter (18mm or 22mm) will not fit into the lugs of the case and compromises use. You can verify the measurement with a digital caliper by measuring internally at the lug, or by consulting the Omega warranty certificate included with the box.

The hybrid ceramic and Sedna Gold case naturally pairs with aged Mississippi alligator in dark brown tones, which reflects the warmth of Omega's proprietary rose gold. Alternatively, vegetable-tanned calf leather offers superior aging patina. For sporting use or humid environments, vulcanized FKM rubber straps or woven NATO fabric are practical choices without aesthetic compromise.

The strap is secured to the case by spring bars, which are inserted perpendicularly to the lugs. Use a strap tool (dedicated instrument) or a small flat screwdriver to press the small buttons at the ends of the bar, retracting it toward the case body. The strap slides off easily. To install the new strap, insert the bar—already mounted on the strap—into the lug seat, ensuring both ends lock into position with an audible click. Avoid applying downward pressure on the bar: the correct lever action is inward toward the watch body.

Yes. All straps with <a href="/pages/termine-glossario/misura-ansa">20mm lug width</a> are compatible. Milano Straps offers handcrafted 20mm straps in alligator, calf, shell cordovan, rubber and fabric, customizable in length, initials and thread color. The Casati Milano atelier's 18-month warranty covers stitching, leather quality and fiber performance.

Durability depends on frequency of wear and materials chosen. Vegetable-tanned alligator, if worn daily in dry environments, lasts 5-7 years before requiring replacement. Shell cordovan lasts 7-10 years thanks to superior fiber density. Standard calf 3-5 years. Accelerating factors of deterioration: constant exposure to water/humidity, intense perspiration, repeated creasing in the same areas. Milano Straps recommends alternating between 2-3 straps for the same watch, dramatically extending the longevity of each.