Marrying aesthetic sophistication with mechanical virtuosity, the Master Ultra Thin collection is a stunning example for Jaeger-LeCoultre?s philosophy of watchmaking. In 2024, the collection is enriched by a new interpretation of the Master Ultra Thin Power Reserve. The elegant dress watch features a subtly modernized case (39.0 x 8.95mm), a new gradient midnight blue sunray dial, and an increased power reserve thanks to an updated movement.

The watchmakers of the Grande Maison have revised the self-winding Caliber 938 to power a new generation of timepieces. Most notably, the power reserve has been increased to 70 hours ? long enough to leave the watch aside for an entire weekend and wear it again on Monday with no need to rewind it or reset the time. This significant gain in power reserve has been achieved without adding to the height of the caliber, which remains 4.9mm thick. The mainspring barrel was redesigned, some key components are now made of silicon, which makes energy transmission smoother by reducing friction of the moving parts, and other minor changes have been made to increase the reliability. The high degree of the finishing has remained the same, though. The exhibition case back displays Geneva stripes, blued screws, perlage, and a partially skeletonized oscillating with.
The power reserve function is a signature complication of Jaeger-LeCoultre, pioneered by the manufacture in 1948 with the introduction of Caliber 481. The Powermatic, disti...