Aquanaut 5167A (Steel, 2007+)

The Aquanaut 5167A is Patek Philippe's slim steel sports watch on a black composite strap. It tells the time and date with three central hands and a window at three. Introduced in 2007, ten years after the first Aquanaut, it enlarged and refined the original design rather than adding more functions.

Its face is almost round, but the frame around it has eight softened sides. The steel is brushed on the broad upper surface and polished along the edges, making the change in angle visible. Inside that frame, large luminous Arabic numerals sit over an embossed grid. The dial is charcoal grey with a darker edge, not a flat sheet of black.

The strap carries a related grid. Where a conventional strap often looks like a separate attachment, this one widens to meet the case and continues the dial's pattern. The first Aquanaut of 1997 used a more strongly raised texture. The 5167's shallower pattern and close-fitting strap make the junction less abrupt, even though the materials remain quite different.

At 40.8 mm across the case from ten to four and 8.1 mm thick, the watch is broad without being deep. An automatic movement winds its spring as the wearer moves. Earlier examples use Patek's calibre 324 SC; the current specification names the 26-330 S C. Both are visible through a transparent sapphire back, where a gold winding weight occupies much of the view.

The steel bracelet version has its own reference, 5167/1A. The 5167A here is the strap watch. That distinction matters to the design: the dark band continues the patterned face while leaving the metal case as a separate, brighter shape in the middle.