Strap for Speedmaster Professional Moonwatch Gemini IV 40th Anniversary

The lug width of the Speedmaster 3565.80.00 is 20mm. This measurement corresponds to the distance between the two lugs of the case and determines strap compatibility. It is essential to verify this dimension before purchasing an aftermarket strap, as an incorrect lug width will not fit properly on the case springs.

There is no absolute choice—it depends on intended use. Black alligator is the most elegant choice for formal settings, developing a refined patina over time. Mahogany brown shell cordovan creates interesting aesthetic contrast with the black dial. Dark gray FKM rubber is ideal for those who want to emphasize the chronograph's sporty character. Vegetable-tanned calf leather offers the best compromise between aesthetics, durability, and value for money.

The Speedmaster 3565.80.00 uses standard 20mm spring bars to secure the strap to the case lugs. Obtain a spring bar removal tool, gently insert it under the spring bar to release tension, and extract the bar from its seat. Repeat on the other side. To install the new strap, reinsert the spring bars into the strap loops and secure them to the case lugs. A simple operation that can be completed in a few minutes with the correct tool.

All straps with 20mm lug width are compatible. The milanostraps.it collections dedicated to 20mm offer alligator, shell cordovan, calf, rubber, and woven leather, customizable in color, size, and stitching. Some original Omega Seamaster 300M models and other heritage collections use the same 20mm, making them interchangeable with your Speedmaster.

Durability depends on material, frequency of use, and climate. A strap in vegetable-tanned leather lasts on average 3–5 years under daily use conditions. Shell cordovan, being more robust, reaches 5–7 years. FKM rubber offers superior durability, up to 7–10 years. Humidity, perspiration, and sun exposure accelerate aging. The Casati Milano atelier offers an 18-month warranty on bespoke straps and support for maintenance and replacement.