Strap for Perpetual Calendar Chronograph 1518 Stainless Steel

The lug width of the Patek Philippe 1518A is 20 millimetres. This measurement refers to the internal distance between the case lugs' attachment pins. It is essential to verify that the strap presents the same width to guarantee perfect fit without looseness or excessive compression at the passants.

For the 1518A, the ideal choice remains alligator, which offers regular grain and natural patina compatible with the historical gravitas of the watch. Alternatively, shell cordovan provides increasing lustre with age, and vegetable-tanned calf offers more contemporary irregular textures. The stainless steel case also accommodates NATO fabric or rubber straps for those preferring a functional approach.

Lug width is measured by calculating the internal distance between the two attachment pins, those small metal axes around which the strap rotates. Use a digital calliper or a ruler with millimetre precision, positioning the measuring tool perpendicularly to the case between the internal points of the pins. For the Patek Philippe 1518A, this distance is exactly 20 millimetres.

Yes, an aftermarket strap crafted artisanally in precious leather and constructed with a 20-millimetre lug width fits the 1518A perfectly. Quality depends upon leather selection, construction precision and finishing details. Casati Milano manufactures bespoke straps following model specifications, guaranteeing absolute compatibility and quality comparable to the Swiss manufacture's historical offerings.

Durability depends on leather quality and intensity of use. A strap in alligator or shell cordovan crafted with vegetable tanning can last 5–8 years of moderate daily wear, extending to 10–12 years with conscious moisture and sunlight management. Casati Milano provides an 18-month warranty against manufacturing defects and recommends periodic maintenance with neutral creams and storage in environments with controlled humidity.