This watch is also known as:
5726A , 5726(or5726A-001) , 5726A-010 .
Patek Philippe Annual Calendar Nautilus with a Stainless Steel Case. Mechanical Self-Winding Movement. Caliber 324 S QA LU 24H, Day, Date, Month in Apertures. Moon Phase and am/pm Indicator. Sweep Seconds Hand, Black Dial, Gold Applied Hour Markers with Luminescent Coating. Strap; Alligator with Rectangular Scales, Hand-stitched, Matt Black, Nautilus Fold-Over Clasp. Screw-Down Crown, Sapphire-Crystal Case Back. Water Resistant to 120m, Case Diameter (10-4 o'clock) 40.50mm