Strap for BC4 Retrograde Day Stainless Steel / Black / Bracelet

The lug width is 22mm. This measurement refers to the distance between the upper and lower attachment pins on the case. All straps compatible with this model must have exactly 22mm width. You can measure this yourself using a digital calliper, placed perpendicularly between the pins: the resulting value is the dimension you require.

For a pilot's chronograph like the BC4, we recommend three complementary options. Tuscan vegetable-tanned leather in vintage brown amplifies the instrumental aesthetic and develops natural patina over time. A grey-stone or military-brown NATO strap maintains the aeronautical identity whilst offering complete reversibility. Black FKM rubber guarantees extreme performance in diving or motorsport contexts. Mississippi alligator, if budget permits, elevates the instrument to ceremonial chronograph status with fine grain and predictable ageing over decades.

The BC4 features 22mm lugs with straight pins, no spring bar. Remove the previous strap: position the watch case-down on a table, locate the pins on either side. Using a spring bar tool or non-abrasive plastic stick, gently push each pin upward to extract it. Repeat on both sides. Insert the new strap by aligning the side holes with the pins and pushing gently until you feel a click of engagement.

Absolutely. The BC4 accepts any aftermarket strap provided the lug width is exactly 22mm. On Milano Straps you will find vegetable-tanned leather, alligator, NATO cordura, rubber and shell cordovan, all tested for mechanical and aesthetic compatibility with the 42.7mm case diameter. Always verify that the lug height (gap between case and strap) is proportionate: an excessively thick strap might interfere with the case.

Tuscan vegetable-tanned leather, if properly maintained, ensures 3-5 years of moderate daily wear. Durability depends on frequency of wear, exposure to moisture and UV radiation, and preventive care with neutral oil every 6-12 months. The material develops natural patina over time, becoming darker and acquiring characteristic texture. The bending area at the lug experiences greater mechanical stress and may fail before the rest of the strap—a sign it is time for replacement. Replacement cost remains modest since the 22mm width offers broad supplier choice.