AUDEMARS PIGUET - Moonphase, Day Date - Reference 25589BA. Serial number C 3XXXX. Caliber 2124 self-winding movement. 18kt yellow gold case with a diameter of 33 mm. White dial with black Roman numerals. Three sub-dials with moon phase at 6 o’clock and date windows at 3 and 9 o’clock. Original leather strap with original 18kt yellow gold pin buckle. 18kt yellow gold screw-down caseback. Sapphire crystal. Circa 1990. Watch in excellent condition. In working order but not tested for accuracy.