The Jaeger-LeCoultre Master Ultra Thin Power Reserve 39mm Q1378420 is an exceptional timepiece that combines a slim profile with a useful power reserve complication. With its 39mm stainless steel case, this watch exudes an understated elegance suitable for both formal and casual occasions. The silver dial features applied hour markers, dauphine hands, and a sub-dial at 10 o'clock indicating the power reserve. This complication allows you to track the remaining power of the watch, ensuring accurate timekeeping. Powered by the Jaeger-LeCoultre Calibre 938 automatic movement, the watch offers precise timekeeping and a power reserve of approximately 43 hours. The transparent case back allows for a view of the beautifully decorated movement. The black alligator leather strap adds a touch of sophistication. With its sleek design, useful power reserve complication, and exceptional craftsmanship, the Jaeger-LeCoultre Master Ultra Thin Réserve de Marche 39mm Q1378420 is a distinguished choice for watch enthusiasts who appreciate a blend of elegance and practicality.