Presented in 18K rose gold and platinum, the 42-mm case is crafted entirely in-house, in the manufacture's own ateliers and leaves nothing to be desired in terms of form and finissage.

The platinum case takes nearly two weeks to craft and becomes  a masterpiece that complies with all directives of the Patek Philippe Seal and fulfills the expectations of discerning Patek Philippe customers. Like all of the manufacture’s platinum models, the Annual Calendar Chronograph Ref. 5905 platinum case features a flawless Top Wesselton diamond between the lugs at 6 o’clock.

Its sapphire-crystal back reveals an automatic mechanical movement crafted with equally uncompromising attention to detail.

The distinctive dial configuration endows the technical aura of the Annual Calendar Chronograph Ref. 5905 with the timeless elegance of a typical Patek Philippe wristwatch.

The rose gold model is complimented with a brown sunburst dial, and the platinum model with either a blue sunburst or an ebony gray-black sunburst dial.

The 18K gold hour and minutes hands are fashioned in a redesigned Dauphine style with three facets and a Superluminova coating on the center ridge. Together with the luminous 5-minute markers, they assure excellent legibility in the dark.

In compliance with the Patek Philippe Seal, the 18k gold applied hour markers are secured by hand with calls for considerable dexterity and absolute concentration in protecting a dial that has already been the subject of many intricate procedures. The date display aperture at 12 o’clock is also crafted in 18k gold.

The Ref. 5905R Annual Calendar Chronograph watch is a gem of precision and dependability with two highly popular complications for men's models.

The sapphire-crystal caseback reveals the delicate craftsmanship of the self-winding mechanical movement, Caliber CH 28-520 QA 24H with combined sweep chronograph/ seconds hand, chronograph with column wheel and vertical clutch, Annual Calendar, day/night indicator and date in aperture at 12 o’clock. At the heart of the movement is the patented Patek Philippe Spiromax® balance spring in Silinvar®.

Comprised of 402 components, 37 jewels and a 21K gold central rotor.

Each movement exhibits an elaborate manual finissage in keeping with the grand Genevan traditions, and an extreme rate accuracy with a tolerance of no more than -1/+2 seconds per day. Such criteria are imposed by the Patek Philippe Seal – a set of very strict standards, recognized by the entire watchmaking industry as the strictest ever compiled.

Patek Philippe's Annual Calendars have been paragons of functionality and dependability for over 20 years.

The patented Annual Calendar needs to be corrected only once a year and is a full calendar that automatically recognizes 30- and 31-day months. If the watch runs without interruption, only one manual correction is required each year at the transition from February to March.

The flyback chronograph epitomizes the role of this timepiece as a precision measuring instrument. The complication within the Annual Calendar Chronograph Ref. 5905R remains true to the traditional column wheel for handling the start, stop, and reset commands. However, it controls the clamp of a vertical disk clutch rather than the lever of a horizontal wheel clutch. This solution is characterized by a high degree of reliability.

As the vertical clutch is virtually friction-free, the center chronograph hand also functions as a permanent seconds hand.