Strap for Speedmaster X-33 Titanium / Black Kevlar

The lug width of the 3990.50.06 is 20mm, measured from lug to lug (centre to centre). This dimension is specific to this model and uncommon in the market: it is essential to verify it before ordering a strap, as most commercial straps are available in 18mm, 20mm, 22mm and variants, but not all manufacturers cover the 20mm range with the same consistency as other sizes.

Vegetable-tanned alligator is the most balanced choice: it offers natural texture that contrasts elegantly with the titanium, ensures durability and develops a fascinating patina over time. If you prefer softness, opt for vegetable-tanned calf. For those seeking a more technical look, a ballistic nylon NATO strap is consistent with the pilot heritage. A strap with a steel <a href="/pages/termine-glossario/deployante">deployant clasp</a> further refines the aesthetics, allowing precise fit even over technical garments.

The X-33 / Z-33 uses straight lugs, not curved. To replace the strap: position the watch on a soft pad, use a spring bar tool or plastic tweezers to avoid scratching the case. Gently press the pin inward from the rear of the case, using leverage to eject the internal spring. Remove the pin completely, repeat on the other side, then insert the new strap by aligning the holes with the lugs and reinserting the pins. Verify that the strap is perfectly aligned before wearing the watch.

The 20mm width refers to the distance between the two pins that make up the case lugs. A "20mm" strap is designed to fit perfectly into this geometry: the strap must fit exactly, with no lateral play or excessive tension. A narrower strap (18mm) will fall between the lugs; a wider one (22mm) will not sit correctly. For this reason, it is crucial to always verify that the purchased strap is certified for 20mm.

A high-quality artisanal leather strap, with vegetable tanning, lasts an average of 3-5 years with daily use, depending on the type of leather and climate conditions. Alligator tends to last longer than calf thanks to denser structural fibres. Leather subjected to constant humidity, tropical climates or environments with chemical agents (salt water, detergents) requires periodic maintenance. A steel <a href="/pages/termine-glossario/deployante">deployant clasp</a> protects the strap from repeated mechanical stress. To extend lifespan, it is recommended not to wear the strap in water and to condition it every 6 months with natural wax.