Jaeger-LeCoultre Master Ultra Thin Réserve de Marche Stainless Steel / Silver / Alligator Ref. Q1378421

The Jaeger-LeCoultre Master Ultra Thin Power Reserve Q1378421 debuted in . This elegant stainless steel dress watch features a 39 mm case with polished and satin-finished surfaces, framing a silvered sunray dial. Refined elements include elongated hour markers, dauphine hands, and three recessed opaline subdials for the power reserve, date, and small seconds functions—each laid out in a symmetrical and harmonious arrangement. Inside ticks the automatic caliber 938, developed and manufactured in-house by Jaeger-LeCoultre. With a silicon escapement and a single barrel, it delivers a 70-hour power reserve. The Q1378421 is paired with a light brown leather strap fitted with a stainless steel double folding clasp.