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Jaeger-LeCoultre

Jaeger-LeCoultre Master Ultra Thin Date Q1238420

The Jaeger-LeCoultre Master Ultra Thin Date (reference Q1238420) is a 39 mm stainless steel watch with a silver sunburst dial. It runs on the automatic caliber 899/1 with a 70-hour power reserve and is water resistant to 50 m.

Specifications

Case

Reference
Q1238420
Collection
Master Ultra Thin
Case size
39 mm
Thickness
7.8 mm
Case material
Stainless steel
Case shape
Round
Crystal
Sapphire
Water resistance
50 m
Bracelet / strap
Alligator leather strap

Dial and bezel

Dial
Silver sunburst

Movement

Movement
Automatic
Caliber
899/1
Power reserve
70 hours
Frequency
28,800 vph
Functions
Date

Production

Production
Current

How it compares within the Master Ultra Thin family

Side by side with other references in the same collection, from the catalog.

ReferenceSizeMaterialDialCaliberYears
Q1238420 (This watch)39 mmStainless steelSilver sunburst899/1—
Q121842039 mmStainless steelSilver sunburst896/1—
Q130847039 mmStainless steelBlack——
Q135842040 mmStainless steelSilver——
Q136252039 mm18k pink goldEggshell925/1—
Q136842039 mmStainless steelSilver sunburst925/12015–
Q136847039 mmStainless steelBlack925/1—
Q136848039 mmStainless steelBlue925/1—
Q137842039 mmStainless steelSilver938—

About the Master Ultra Thin family

Master Ultra Thin is Jaeger-LeCoultre's line of very slim dress watches, drawing on the manufacture's long history of thin movements. It includes time-only models, moon phases, perpetual calendars and tourbillons in round, classic cases.

The catalog includes references with calibers such as 896/1, 899/1 and the moon-phase 925/1, in steel, pink gold, red gold and platinum. Dealers identify the function and size from the reference and check the strap, buckle and papers.

Quick answers

What size is the Jaeger-LeCoultre Master Ultra Thin Date Q1238420?
The Jaeger-LeCoultre Master Ultra Thin Date Q1238420 has a 39 mm case, 7.8 mm thick.
What movement does the Jaeger-LeCoultre Master Ultra Thin Date Q1238420 use?
It uses the automatic caliber 899/1, with a 70-hour power reserve.
How water resistant is the Jaeger-LeCoultre Master Ultra Thin Date Q1238420?
It is water resistant to 50 metres.
Is the Jaeger-LeCoultre Master Ultra Thin Date Q1238420 still in production?
Yes, it is a current reference.
What is the Jaeger-LeCoultre Master Ultra Thin Date Q1238420 made of?
The case is stainless steel. Bracelet or strap: Alligator leather strap.

Catalog facts checked September 2026.