This watch is also known as:
3998-1J , 3998.1J , 39981J .
Movement: mechanical with automatic winding; Patek Philippe Caliber 315 SC; 29 jewels; 21,600 vph; hallmarked with the Geneva Seal. Case: in 18 karat yellow gold; 34 x 7.7 mm (excl. lugs & crown); sapphire crystal; yellow gold crown; screw-on case back. Water-resistant to 25 meters.