Tantalum and Rose Gold
When Audemars Piguet introduced the ref 5554 in 1984, it was the first sports watch automatic perpetual calendar ever made by any brand, during the years AP with a great sense of innovation, experimented and as in the present watch introduced new materials as a Tantalum, which were not commonly used in the horological manufactures. Expensive, Extremely hard, high resistance to corrosion and wear, the tantalum is most often used in the aeronautical and medical industries.
Bond with gold, ordinary known as a soft and flexible material makes this watch a Ying and Yang match. With an extremely limited production of only 16, 39 mm Skeletonized Tantalum and Gold as confirmed by AP, is one of the rarest RO ever made.