Jaeger-LeCoultre · Master Control

Strap for Master Control Calendar Stainless Steel / Silver

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

Lug width20 mm
Case diameter40 mm
ReferenceQ4148421 (aka: 4148421)
FamilyMaster Control
MovementJaeger-LeCoultre caliber 866AA Hours, Minutes, Small Seconds | Date, Day, Month | Moonphase
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 Master Control Q4148421 (aka: 4148421)

Selected for the 20 mm lug width · workshop selection

All 20 mm straps →

The Master Control Q4148421 (aka: 4148421), seen from the bench

The Jaeger-LeCoultre Master Control Q4148421 is a contemporary evolution of a collection established in 1992, featuring a 40 mm stainless steel 316L case with a rigorous geometric design and harmonious proportions. It houses the caliber 866AA, an in-house automatic movement with integrated chronograph, date, day, month, and moonphase display, visible through a sapphire caseback. The 20 mm lug width is a distinctive specification that requires straps with precisely 20 mm internal passers for proper aesthetic integration with the case.

Frequently asked questions

What is the lug width of the Jaeger-LeCoultre Master Control Q4148421?

The Jaeger-LeCoultre Master Control Q4148421 features a lug width of 20 millimetres. This is a specific measurement that requires straps with lugs exactly 20 millimetres wide internally. Straps measuring 18 or 22 millimetres cannot be adapted without compromising the aesthetic transition between case and wrist.

Which strap do you recommend for the Master Control Q4148421?

For the Master Control Q4148421 we recommend alligator in dark brown (cognac) tones if the dial is blue, or vegetable-tanned calf in pearl grey for lighter dials. Those seeking a strap capable of developing rich patina over time should consider burgundy shell cordovan. The texture must harmonise with the sharp shoulders of the case and the classical character of the dial.

How do you change the strap on a Jaeger-LeCoultre Master Control Q4148421?

The strap is changed by removing the spring bars that connect the lugs to the case. Use a dedicated spring bar tool, inserting it beneath the bar with the watch securely positioned on a soft surface. Press the bar inward to release it from one side, extract it completely, remove the old strap, insert the new one, and secure the bar on the opposite lug. The procedure takes less than one minute per bar.

Can I use a compatible aftermarket strap on the Master Control Q4148421?

Yes, any high-quality artisanal strap with a 20mm lug width is compatible with the Q4148421. Aftermarket straps from reputable makers often offer superior construction quality, richer materiality, and customisation options not found in OEM proposals. Ensure the strap is fitted with removable standard spring bars.

How long does a leather strap last on a Jaeger-LeCoultre Master Control Q4148421 with daily use?

A high-quality artisanal leather strap, worn daily, has an average lifespan of 3-5 years before requiring replacement. Longevity depends on material: shell cordovan lasts longer, vegetable-tanned calf offers a balanced ratio between durability and aesthetic patina, alligator tends to develop natural creasing after four years. Intermittent use (non-daily) extends lifespan to 7-8 years.

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