The Patek Philippe Aquanaut, introduced in 1997 as ref. 5060A, is the brand's second sports watch and the Nautilus's younger, more casual sibling — designed from the outset with a more adventurous spirit and a composite strap rather than the Nautilus's integrated metal bracelet. The Aquanaut's case is a rounded octagon, clearly related to the Nautilus in DNA while establishing its own proportions and personality. The embossed dial, with its horizontally textured pattern echoing the rubber strap's surface, gives the Aquanaut a cohesive, sporty character that distinguishes it from every other Patek Philippe reference. The Aquanaut's key references include the 5167A in stainless steel — the most widely traded pre-owned example — as well as the 5168G in white gold with a khaki green dial, which became one of the most desirable references in recent Patek history. The Aquanaut Travel Time ref. 5164 and the Aquanaut Luce ladies references add complication and gem-setting options to the lineup. Pre-owned Aquanaut prices have tracked closely with the Nautilus on the secondary market, reflecting the brand's constrained production and consistent demand. DeMesy & Co. in Dallas has been a trusted source for pre-owned Patek Philippe Aquanaut references since 1987.