Fully functional! Battery replacement and inspection by a watchmaker in November 2025! Very rare vintage collector's item, first-hand! Very interesting: the date display runs around the outside in a ring. Hour and minute display via hands from the center, small seconds with seconds stop for setting the time to the second at 6 o'clock, date display at the edge of the dial, indicated by two red lines for the respective day of the week. The watch has hardly been worn and is in impeccable condition. However, the leather strap shows signs of wear. The vintage IWC Portofino Chronograph IW3731-05 has a 35.00 mm x 8 mm stainless steel and yellow gold case and a white dial. It is equipped with the "MecaQuartz" caliber 631 chronograph movement and was purchased in 1992. Sapphire crystal. Screw-down crown. Stainless steel case back, secured with four screws. The papers are included, and the original box is also included, but it is not in good condition as the material has deteriorated over the years. The watch should not be stored in it as the interior material rubs off. The outer box is included but shows signs of wear. The watch was stored in a neutral box in a safe.