Strap for 1815 Kalenderwoche

The lug width is 20 mm. This measurement is standard across all 245.021 examples and can be verified on the inside shoulder of the case, where the strap attaches via spring bars. Always confirm this measurement before ordering a strap to ensure proper compatibility.

Natural alligator is the most coherent choice with Glashütte's minimalist philosophy: the discreet longitudinal grain harmonises naturally with yellow gold, and the patina developing over time accompanies the controlled ageing of the case. Valid alternatives include vegetable-tanned calf for more pronounced texture, or dark brown shell cordovan for sophisticated colour harmony.

Remove the spring bars using a dedicated tool or flat blade, gently levering the small containment ball. Extract the spring bar from its seat in the case, then detach the old strap. Align the new strap to the case shoulders, insert the spring bar into both lug holes, and ensure the containment ball clicks into position. Test the security by tugging the strap before wearing.

Yes, any strap with 20 mm lug width is compatible. A. Lange & Söhne applies no proprietary restrictions that prevent the use of high-quality artisan straps. Choosing an aftermarket strap in alligator, calf, or shell cordovan does not compromise watch functionality and further enhances your investment in a yellow gold case.

Longevity depends on tannage and usage patterns. High-quality alligator or vegetable-tanned calf resists 3-5 years with daily wear, developing visible patina over time. Shell cordovan is more robust and may last 5-7 years whilst maintaining elasticity. Occasional use or rotating multiple straps significantly extends service life. Casati Milano offers 18-month warranty against manufacturing defects.