Jaeger-LeCoultre
Master Control Q4138130 (aka: 4138130)— lug 20mm

The lug width of the Jaeger-LeCoultre Master Control Q4138130 — also known as 4138130 — is 20 mm. This measurement is taken with a digital caliper at the attachment point between the lugs, where the strap connects. It is one of the most common widths in haute horlogerie and ensures broad availability of compatible quality straps.

For the Q4138130, with its white dial and blue details, a deep night blue or glossy black alligator belly strap is the most coherent choice with the piece's formal identity. Box-calf leather is ideal for business and dress contexts, while a heavy nylon navy NATO strap is perfect for daily wear. For summer, a vulcanized rubber strap in black maintains functionality without compromising aesthetics.

Strap replacement on the Q4138130 is performed using standard 20 mm spring bars housed in the watch lugs. With a dedicated lever tool or spring bar tool, you compress the bar on one side and extract the strap. The operation requires care to avoid scratching the steel lugs: it is recommended to use plastic protectors or consult a watchmaker for initial changes.

Yes: any strap with a 20 mm attachment is technically compatible with the Q4138130. For optimal aesthetic results, it is preferable to choose straps with curved ends or verify the curve of the lugs for the specific model. Milano Straps offers a selection of artisanal 20 mm straps made in alligator, calf, NATO, and rubber, produced by the Casati Milano atelier with customizable finishes.

The lifespan of a leather strap depends mainly on the type of leather, care, and frequency of use. A quality alligator strap, with regular maintenance using products specific to reptile leather, lasts on average 3 to 5 years with daily wear. Box-calf leather has a similar lifespan but is more sensitive to humidity and perspiration. All Casati Milano straps are covered by an 18-month warranty against manufacturing defects.