One of my favorite new additions to Patek Philippe for 2011 is an addition to the Aquanaut line, reference 5164A-001. This new model brings a dual time complication to the family of aquanaut watches. Only available in stainless steel, the case measures 40.8 millimeters, a mere 0.8 millimeters larger than the 5167 model. The black embossed dial has gold applied numerals and luminescent hour markers. The dial displays has a dual time zone mechanism which indicating local and home time indicating local and home time as well as local and "home" day/night indication in apertures. The local date and sweep seconds are indicated by hand.

The Aquanaut 5164A is powered by the self-winding mechanical movement Caliber 324 S C FUS which measures 31 millimeters in diameter and 4.82 millimeters high. The movement contains a total of 294 parts and 29 jewels and allows for a maximum 45 hour power reserve. The cases screw down crown and sapphire-crystal case back help achieve the watches water resistance to 120 meters. The watch is completed by a "Tropical" composite strap and an Aquanaut fold-over clasp in steel.