Strap for Senator Perpetual Calendar Stainless Steel / Black / Alligator / Pin

The lug width of the 100-02-25-12-01 is 20mm. This is the vertical distance between the two integrated lugs of the case. To verify, measure the space perpendicularly using a digital calliper. The acceptable tolerance is 19.5mm–20.2mm to ensure precise strap fitting without play.

For a timepiece of this technical and formal calibre, the ideal strap is in full-grain leather (calf or alligator) with vegetable tanning. Dark brown calf (mahogany/chestnut tone) enhances the silver dial; pearl grey alligator conveys sophistication. Both develop patina over time. For sporting contexts, a cotton NATO strap or FKM vulcanised rubber represent robust alternatives.

The Senator features lugs that are soldered to the case, making strap replacement impractical for end-users without specialist intervention. It is advisable to consult an authorised Glashütte Original service centre or an experienced horologist specialising in luxury timepieces, who possesses the specific tools for spring bar extraction and case integrity preservation.

Yes. High-quality aftermarket straps with 20mm lug width are compatible once the original strap is removed by a horologist. Milano Straps offers a collection of artisanal leather straps (alligator, calf, shell cordovan), NATO, and vulcanised rubber, all available in 20mm width. The choice must respect the formal aesthetic of the timepiece.

A full-grain leather strap (calf, alligator, cordovan) with vegetable tanning, subjected to regular wear, has an estimated lifespan of 4–7 years. Longevity depends on frequency of use, ambient humidity, and maintenance. Uniform patina indicates natural ageing; structural creases or detachment suggest replacement. NATO and vulcanised rubber straps offer superior durability (8–10 years) in high-humidity environments.