Strap for Speedmaster Professional Moonwatch Plexi / See-Through / Leather

The lug width of the 3872.50.01 model is exactly 20mm. The lugs are crafted from forged steel with a slightly curved profile, typical of the 42mm Moonwatch case. Do not confuse with earlier versions featuring 18mm lugs: this reference requires 20mm straps without exception.

The best options are: black alligator for formal wear (fine grain, visual contrast with brushed steel), grey or blue vegetable-tanned calf for daily use with natural patina development over time, shell cordovan for decade-long longevity, waxed canvas NATO for vintage-operative authenticity, black FKM rubber with deployant clasp for sports and aquatic environments.

The Moonwatch uses standard spring bars of 1.8mm. With a spring bar tool, insert the lever between the spring and the lug, decompress slightly and extract the spring from its seat. Next, place the spring in the new strap, insert manually and verify proper engagement. The operation takes 30 seconds per lug and is reversible without risk to the case.

Yes, all straps with 20mm lug width are compatible. However, construction quality and finishing vary enormously. For the Moonwatch, we recommend leather tanned with vegetable tanning processes and buckles in 316L stainless steel (identical to the case): this combination ensures longevity and aesthetic harmony with the watch's spirit.

Durability depends on material: standard calf (mixed tanning) 2-3 years with daily wear; vegetable-tanned calf 5-8 years with improving patina; shell cordovan 10-15 years without deterioration. Critical factors are body moisture, sun exposure, cleaning frequency and weekly strap rest (rotating multiple straps extends lifespan by up to 40%).