Jaeger-LeCoultre · Master Ultra Thin
Strap for Master Ultra Thin Réserve de Marche Stainless Steel / Silver / Alligator
Takes 20 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.
Lug width
20mm
Lug width20 mm
Case diameter39 mm
Reference1378420 (aka: Q1378420)
FamilyMaster Ultra Thin
MovementJaeger-LeCoultre caliber 938 hours, minutes, small seconds | date | power reserve indicator
CaseStainless Steel
Straps for the Master Ultra Thin 1378420 (aka: Q1378420)
Selected for the 20 mm lug width · workshop selection
Black Rubberized Alligator Strap with Red Tribal Stitching€185
Matte Dark Gray Alligator Strap€195
Matte Black Alligator Strap — Minimal Stitching€149
Vintage Brown Calfskin Strap — Natural Patina€98
Hammered calfskin strap in cuoio€98
The Master Ultra Thin 1378420 (aka: Q1378420), seen from the bench
The Jaeger-LeCoultre Master Ultra Thin 1378420 is a 39mm stainless steel watch from the Master Ultra Thin collection. It features the in-house caliber 938 automatic movement with hours, minutes, small seconds, date, and power reserve indicator, offering approximately 43 hours of autonomy at 28,800 vibrations per hour. The watch has a lug width of 20mm and a case thickness of just 7.45mm, embodying refined proportions and understated elegance with a white dial and subsidiary seconds at six o'clock.
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.
Request an appointment →Casati Milano · Via XX Settembre 15, Milan · by appointment only