Strap for Speedmaster Professional Moonwatch Japan Racing

The lug width of the 3570.40.00 is exactly 20mm. This measurement is the historic standard of the Speedmaster Professional and is fundamental for selecting the correct replacement strap. Measuring the lug width means gauging the perpendicular distance between the two attachment points of the case – an error of half a millimetre would create visible asymmetries on the wrist.

The choice depends on usage and personal aesthetics. Alligator leather with vegetable tanning and ivory stitching directly evokes Apollo-era straps and represents the ultimate formal choice. Shell cordovan offers extraordinary aging and deep patina development. Chrome-tanned calf ensures lightness and breathability for those seeking everyday wearability. A NATO strap in polyamide introduces sporting versatility without undermining the model's military DNA.

The Speedmaster uses removable spring bars. A dedicated spring bar tool is required to gently lift the lugs on the sides of the case, detach the old strap, and insert the new one. The operation demands precision to avoid scratching the case. If inexperienced, we recommend having it performed at the Casati Milano atelier, which completes the change within 48 hours.

All straps in 20mm lug width are compatible with the Speedmaster 3570.40.00. Online you will find vast catalogues of calf, alligator, shell cordovan, NATO, and rubber in this size. Quality varies significantly: we recommend artisanal straps in vegetable tanning or shell cordovan from specialized suppliers, which guarantee elegant aging and durability exceeding 5-7 years.

Durability depends on the material, tanning method, and intensity of use. A chrome-tanned calf strap typically lasts 3-4 years of daily wear. Alligator and shell cordovan with vegetable tanning resist 6-8 years if maintained regularly. Leather ages naturally over time, developing character and uniqueness. Casati Milano guarantees 18 months on all made-to-measure straps, with the possibility of subsequent regeneration and maintenance.