1970s IWC Ref.866AD "Big Ingenieur" Automatic Date rare 18K yellow gold

Manufactured in the 1970s – International Ref. 866AD "Big Ingenieur" Automatic Date
This is an extremely rare model crafted in 18K yellow gold.
Among the Ref. 866 models, which are most commonly seen in stainless steel, this is a rare piece made with 18K yellow gold.
It’s a precious timepiece that showcases the unique volume of the Big Ingenieur with its over-37mm case size, the solid heft characteristic of a full-gold model, and a luxurious silver dial enhanced by gold indices and gold hands.
It is equipped with the renowned International caliber Cal. 8541B, featuring both a quickset date mechanism and a hacking seconds function—adding to its appeal as one of the most practical and top-tier vintage International models.