Strap for K-011

The lug width of the Karoshi K-011/OS-01 is exactly 20mm. This measurement is proportionate to the 50mm case diameter and represents an inviolable design choice of the original concept. Measuring correctly is essential: position a digital calliper perpendicularly against the two internal lug shoulders and verify that the result is 20mm ±0.2mm tolerance.

There is no universally "best" strap, as selection depends on usage context and desired aesthetics. For formal elegance, natural alligator with vegetable tanning is recommended; for pure minimalism, a polyamide NATO; for daily versatility, European calf with vegetable tanning; for intensive activity, hot-vulcanised FKM rubber. Milano Straps offers all these options in 20mm sizing, guaranteeing absolute dimensional conformity.

The Karoshi K-011/OS-01 features integrated lugs, meaning the strap attaches through the case's specific passants. For replacement, use a spring bar removal tool to gently extract the internal retention spring. Insert the new 20mm strap by precisely aligning the passants, then reinsert the spring until you hear the locking click. If uncertain about the procedure, consult a specialised watch technician.

An aftermarket strap is compatible with the K-011/OS-01 only if it rigorously respects the 20mm lug width specification. However, not all straps of this size are manufactured with identical dimensional tolerances: even minor variations (exceeding ±0.2mm) can cause oscillation during wear. Milano Straps supplies 20mm straps verified and certified for absolute compatibility with the Karoshi, eliminating the risk of constructive inaccuracies.

A natural leather strap with vegetable tanning, under daily use, typically lasts 3-5 years before displaying structural wear signs (cracks, edge thinning). This longevity depends on maintenance, ambient humidity, and frequency of use. Superior quality alligator or shell cordovan can last 5-8 years with appropriate care. Hot-vulcanised FKM rubber maintains integrity for 4-6 years under normal conditions. Milano Straps offers strap regeneration services to further extend useful life.