Strap for Seamaster Aqua Terra 150M Co-Axial 41.5 Stainless Steel / Red Gold / Grey / Bracelet

The lug width of the 231.20.42.21.06.001 is 20mm. This measurement represents the distance between the two horizontal pins where the strap attaches to the case. It is essential to verify this measurement before purchasing an aftermarket strap, as 19mm or 22mm models are not compatible.

Vegetable-tanned alligator is the most balanced choice for this two-tone model: the vertical grain enhances the teak deck texture of the dial, and the patina develops beautifully over time. Brown shell cordovan is a luxurious alternative. For sporty use, structured black rubber amplifies the contrast between red gold and steel.

The strap is removed by pressing the spring bar terminals and sliding them outward from the lugs. This procedure requires a dedicated tool (spring bar tool) to avoid scratching the case. For more delicate replacement work, it is advisable to contact an authorized service or a specialist such as Casati Milano atelier.

Yes, all straps with 20mm lug width are compatible with the 231.20.42.21.06.001. milanostraps.it offers handcrafted straps in alligator, shell cordovan, grained calf, and rubber, customizable in color, size, and stitching. Casati Milano atelier can create custom straps by private consultation.

A premium leather strap — alligator or shell cordovan — lasts an average of 3-5 years with regular use and ordinary maintenance (cleaning, drying, moisture protection). Natural rubber has comparable durability. Factors affecting longevity are: frequency of use, climatic conditions, perspiration levels, sun exposure. milanostraps.it offers an 18-month warranty on all handcrafted straps.