Zenith
Class 03.0510.400/04.C491— lug 20mm

The Zenith Class 03.0510.400/04.C491 has a 20mm lug width. This measurement is specific to Zenith chronographs of this generation and must be verified precisely before purchasing a strap, as it is not compatible with different widths such as 18mm or 22mm. The correct measurement is taken by measuring internally at the lug seat where the spring bar sits.

For the Zenith Class 03.0510.400/04.C491, we recommend mississippi alligator in natural or deep brown tone for a formal-elegant look, or premium calf leather in burgundy or black for greater tactile refinement. For sporty interpretations, technical rubber in deep blue or burgundy creates interesting color contrasts. NATO works less effectively for visual balance on this 40mm case.

Changing the strap on the Zenith Class requires using a spring bar tool (lever tool) to insert and remove the spring bar ends from the lateral slots of the lug seat. Insert the spring bar tool into the side grooves, apply gentle inward pressure to release the bar end, then pull the strap outward. Reverse the procedure to install the new strap. If uncertain, consult a specialist: improper execution can compromise the spring bar seal.

Yes, any strap with a 20mm lug width is physically compatible. However, build quality and material selection vary greatly in the aftermarket. The handcrafted straps from Casati Milano guarantee precise stitching, premium leathers, and finishes that respect your Zenith's aesthetics, along with professional after-sales support and an 18-month warranty.

A quality leather strap, such as those handcrafted to order, lasts an average of 3-5 years with daily use, provided basic maintenance is performed (drying after moisture exposure, avoiding prolonged soaking). Premium alligator and calf age better than budget leathers, developing patina and increasing in aesthetic value. Casati Milano offers replacement and regeneration services that significantly extend the life of the original strap.