Strap for Speedmaster 125 Pulsometer

The lug width is 20mm. This measurement is the internal space between the two metal lugs that connect the case to the strap. You can verify it by positioning a digital caliper perpendicular to the cylinder that serves as the connector, measuring its internal distance. Precise verification is essential before ordering any aftermarket strap.

To maintain consistency with the medical-professional identity of the chronograph, an alligator with vegetable tanning and fine grain represents the most suitable choice. Its refined appearance and superior wear resistance respect the constructive spirit of the 1970s. Alternatively, a shell cordovan with natural pull-up offers structural compactness and elegant luster without betraying instrumental austerity.

The lugs are connected to the case by spring bars. Use a dedicated tool (spring bar tool) to compress the pin: insert the flat tip of the tool into the lateral groove of the pin, compress slowly until the pin retracts, then extract the lug. Repeat from the opposite side. To install the new strap, reinsert the pins by compressing them until you hear the locking click. Delicate operation: if inexperienced, consult an expert.

Yes, any strap with a 20mm lug width is compatible. Milano Straps artisanal straps are crafted to specification for the ST 378.0801 Puls, with customization options in leather (alligator, shell cordovan, calf), color, and stitching thread. Verify that the lug has been constructed to this exact width.

Durability depends on frequency of use and leather quality. An alligator or shell cordovan with vegetable tanning, worn daily, maintains full functionality for 3-5 years before potentially requiring repairs at attachment points. With occasional use, longevity extends to 8-10 years. Casati Milano straps include an 18-month warranty and restoration options.