Arnold & Son · Instrument Collection

Strap for Time Pyramid

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

Lug width20 mm
Case diameter45 mm
Reference1TPAS.S01A.C124S
FamilyInstrument Collection
MovementArnold & Son caliber A&S6003 hours, minutes, jumping seconds
CaseStainless Steel

Spring bar

Swiss Standard universal spring bars

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

Straps for the Instrument Collection 1TPAS.S01A.C124S

Selected for the 20 mm lug width · workshop selection

All 20 mm straps →

The Instrument Collection 1TPAS.S01A.C124S, seen from the bench

The Arnold & Son Instrument Collection model 1TPAS.S01A.C124S features a 44.60 mm stainless steel case paired with a proprietary A&S6003 caliber movement. The watch incorporates a jumping seconds complication and measures 20 mm at the lugs. Inspired by 18th-century maritime chronometers founded by John Arnold, this contemporary instrument balances precision engineering with functional design principles rooted in nautical navigation history.

Frequently asked questions

What is the exact lug width of the Arnold & Son Instrument Collection 1TPAS.S01A.C124S?

The lug width of the 1TPAS.S01A.C124S is 20 millimetres. This measurement represents the internal distance between the two pins located on the lugs of the case. Any strap intended for this model must have precisely 20mm width for perfect fit and secure attachment.

Which strap is most suitable for the Arnold & Son Instrument Collection 1TPAS.S01A.C124S?

The ideal strap depends on intended usage. For formal contexts, an alligator strap with vegetable tanning in dark brown honours the brand's English sartorial tradition and develops a rich patina over time. For robust daily wear, shell cordovan guarantees twenty-year durability without failure. For sport-tool styling, a slate-grey NATO maintains the collection's technical identity. Rubber represents the most functionally advanced solution for humid environments or professional work.

How do I change the strap on my Arnold & Son Instrument Collection 1TPAS.S01A.C124S?

Strap change is executed by removing the side pins (spring bars) that connect the lugs to the case. Using a dedicated strap-change tool, apply gentle pressure to extract the pin from its housing. Once the pin is removed, the old strap detaches completely. The new 20mm strap is installed by inserting the opposite pin through the lug hole, then pushing the pin into the second housing until you hear the locking click. Avoid forcing to prevent damage to the internal spring.

Can I use a quality aftermarket strap on this Arnold & Son watch?

Yes, a quality aftermarket strap constructed to the 20mm standard is entirely compatible. Milano Straps supplies artisanal straps crafted from premium materials—alligator, shell cordovan, vegetable-tanned calf, rubber—that equal or exceed OEM straps in construction quality. Choosing an aftermarket option allows you to diversify your watch's aesthetics whilst maintaining perfect mechanical compatibility.

What is the expected lifespan of a leather strap for the 1TPAS.S01A.C124S?

A quality leather strap has variable durability based on material and usage. Vegetable-tanned alligator resists 7-10 years of intensive daily wear before requiring replacement. Vegetable-tanned calf guarantees 5-7 years. Shell cordovan, owing to its exceptionally high fibre density, can last 15-20 years even with frequent use. Lifespan extends further with regular maintenance: dry the strap after water contact and occasionally apply natural-based conditioner to significantly extend leather life.

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