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A. Lange & Söhne · Lange 1

Strap for Grand Lange 1 Moonphase Yellow Gold

Takes 20 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.

Lug width

20mm
20 mm strapsAll A. Lange & Söhne
Lug width20 mm
Case diameter41 mm
Reference139.021
FamilyLange 1
MovementA. Lange & Söhne caliber L095.3 Hours, Minutes, Small Seconds | Big Date | Moonphase | Power Reserve Indicator
CaseYellow Gold

Spring bar

Swiss Standard universal spring bars

The right category for this model · 316L steel, all lug widths 13–26 mm

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Straps for the Lange 1 139.021

Selected for the 20 mm lug width · workshop selection

All 20 mm straps →

The Lange 1 139.021, seen from the bench

The A. Lange & Söhne Lange 1 model 139.021 in yellow gold features the L095.3 calibre and embodies functional asymmetry with exceptional readability. Introduced in 1994, this 18-carat yellow gold timepiece measures 38.5 mm in diameter with a 20 mm lug width. The asymmetrical platinum plate organises every function around clarity, displaying the movement with total visibility characteristic of contemporary German watchmaking.

Frequently asked questions

What is the lug width of the A. Lange & Söhne Lange 1 reference 139.021?

The Lange 1 model 139.021 features a <a href="/pages/termine-glossario/misura-ansa">lug width</a> of 20mm. This dimension is standard for the 41mm case and fully compatible with custom straps. Measurement is taken between the case lugs—the space where the strap ends insert via spring bars.

What strap material best suits a yellow gold A. Lange & Söhne Lange 1?

We recommend <a href="/pages/termine-glossario/alligatore">alligator</a> or <a href="/pages/termine-glossario/shell-cordovan">shell cordovan</a>. Hermès alligator or Nile crocodile offer natural texture and patina that complement the gold's noble ageing. Shell cordovan provides anatomical fit and superior durability. Both sourced with <a href="/pages/termine-glossario/concia-vegetale">vegetable tanning</a> to preserve the watch's collectible value.

How do you change the strap on an A. Lange & Söhne Lange 1?

Position the watch on a soft pad. Use a spring bar tool (or small flat screwdriver) to gently compress the spring located beneath the lug. This action releases the terminal from the case. Repeat on the opposite side. Insert the new strap by aligning the terminals into their seats and release the springs—you'll hear a click. Avoid excessive force: yellow gold is soft.

Can you use an aftermarket strap on the A. Lange & Söhne Lange 1 139.021?

Absolutely. Any strap with 20mm lug width is compatible with the 139.021. The recommendation is to select leather and <a href="/pages/termine-glossario/deployante">deployante</a> buckles that match the watch's construction quality—Rolex, Patek Philippe, or custom yellow gold clasps. An artisanal strap from <a href="https://milanostraps.it/collections/cinturini-orologi-per-misura-ansa-20mm">milanostraps.it in 20mm</a> transforms your wrist into a statement of aesthetic coherence.

How long does a leather strap last on a Lange 1?

Duration depends on tanning method and usage. Alligator or shell cordovan with vegetable tanning maintains functionality for 4-6 years under daily wear, with patina improving over time. Synthetic or fast vegetable-tanned leather lasts 2-3 years. Critical factors: UV exposure (degrades leather), body perspiration (weakens fibres), humidity levels. An artisanal strap with hand-finished details can exceed these timeframes through careful material selection and manual construction—every stitch is verified.

The next step

The right strap isn't chosen. It is built, together.

From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.

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Casati Milano · Via XX Settembre 15, Milan · by appointment only