Omega
Speedmaster Moonwatch 3875.30.31— lug 20mm

The Omega Speedmaster Moonwatch 3875.30.31 features a lug width of 20mm. This dimension is the distance between the two lugs to which the strap is attached. Omega selected 20mm for the 3875.30.31 to maintain elegant proportions on the 42mm case, avoiding visual heaviness while ensuring a solid presence on the wrist.

The choice depends on your intended use and desired aesthetic. For a classic formal chronograph look, dark brown or black alligator leather offers natural patina development and versatility. If you prefer understated elegance with a contemporary texture, vegetable-tanned Barenia calf develops a fascinating patina over time. For those who wish to maintain the original sportive and professional character of the Moonwatch, a grey or black NATO canvas strap respects the instrument watch's functional spirit.

The 3875.30.31 strap is replaced by removing the two spring bars that pass through the lugs. Use a spring bar tool or consult a watchmaker: position the tool under the spring bar, gently lift to release the internal spring, and slide the bar out of the lug. Repeat on the other side. The old strap is now free. To install the new one, reinsert the spring bars starting from one side, align the other end of the strap to the opposite lug, and snap the second bar into place. Verify the strap is secure before wearing the watch.

Yes, provided it has a lug width of 20mm. Artisanal straps compatible with this width, such as those offered by Milano Straps.it, fit perfectly on the lugs of the 3875.30.31. It is important to verify that the strap is designed to accommodate standard 20mm spring bars and that the total length is appropriate for your wrist (Speedmasters typically require 12mm of upper passage and 8–9mm of lower passage).

Durability depends on the material and conditions of use. Genuine alligator with vegetable tanning, subjected to daily wear under normal conditions (avoiding prolonged exposure to salt water or direct sunlight), maintains full functionality for 3 to 5 years. High-quality calves, such as Barenia, develop a prized patina and can last similarly. The warranty on artisanal craftsmanship typically covers 18 months from delivery, during which any manufacturing defect is resolved at no cost.