Patek Philippe 5164A (Pre-owned - Good) — USD 97,999 on eBay

The Patek Philippe Aquanaut reference 5164A represents a significant evolution in the collection s history, introducing the brand s first travel time complication to the sporty Aquanaut line. Launched as part of Patek Philippe s expansion of the Aquanaut family beyond simple time-only models, this reference bridges the gap between the manufacture s renowned travel time expertise and contemporary sports watch design. The 5164A demonstrates Patek Philippe s commitment to bringing haute horlogerie complications to their modern steel sports watches, establishing it as a cornerstone reference that elevated the Aquanaut s status within the brand s hierarchy. At the heart of the 5164A beats the automatic caliber 324 S C, a sophisticated movement that powers the dual time zone functionality with characteristic Patek Philippe precision. This caliber features a 21K gold rotor and delivers a power reserve of approximately 35-45 hours, while maintaining the manufacture s exacting standards for finishing and reliability. The movement enables intuitive travel time operation through pushers integrated into the case, allowing the local hour hand to advance in one-hour increments while maintaining running seconds and preserving the home time display. The 5164A s design language perfectly embodies the Aquanaut s modern aesthetic philosophy, featuring the collection s signature embossed Tropical composite strap and the distinctive rounded octagonal case profile scaled to 40.8mm in diameter. The black dial presents exceptional legibility with applied luminous markers and the characteristic dual time zone layout, while the fixed bezel and sapphire crystal contribute to the watch s 120-meter water resistance. From a collectibility standpoint, the 5164A occupies a unique position as the sole steel Aquanaut travel time model, making it highly sought after by collectors who appreciate both the practical complications and the reference s role in defining the modern Aquanaut collection s expanding complexity.