Jaeger LeCoultre, Master, Model: 1372520 Automatic Mechanical 18k rose gold 39mm • Case: 18K rose gold, diameter 39mm, classic size for formal wear • Strap: Original factory dark brown alligator leather strap • Movement: Jaeger-lecoultre's self-produced Cal.938 automatic mechanical movement Analysis of the three major functional areas of the dial Left upper sector window RESERVE DE MARCHE: 40-hour power reserve display, the pointer reading indicates the remaining battery life of the movement. Upper right arc-shaped dial: 31-day retrograde calendar, the pointer moves along the date in an arc, and automatically jumps back to No. 1 at the end of the month. 6 o 'clock small disc: Independent small seconds dial, blue steel seconds hand with cross-scale