Audemars Piguet Royal Oak Selfwinding “50th Anniversary” Steel Ice Blue Dial Men’s Watch 15550ST. The Audemars Piguet Royal Oak Self-winding “50th Anniversary” is a beautiful timepiece that celebrates the brand’s rich history. This watch features a stunning 37mm case made of stainless steel, a comfortable bracelet, and an ice blue dial that is sure to impress. The Audemars Piguet Royal Oak Self-winding is the perfect watch for those who appreciate fine craftsmanship and classic design. Case Material: Stainless Steel. Bracelet Material: Stainless Steel. Box & Papers: Original box, original papers.