The Annual Chronograph is one of Patek Philippe's most important models, featuring the Swiss watchmaker's very first in-house manufactured automatic chronograph. Traditionally an elegant and refined timepiece, Patek Philippe made a surprise change to this classic watch in the Annual Chronograph ref. 5960/1A. This latest model, which replaces all others, features the signature mono-counter chronograph and tri-aperture annual calendar on a white opaline dial, but instead of the classic gold case it is now crafted in mirror-like, polished stainless steel and presented on a steel droplet bracelet. The use of this everyday material gives it a casual and sporty feel - a move away from its more formal predecessor. The mono-counter chronograph at 6 o'clock displays the 60-minute and 12-hour counter as well as the day/night indicator in one aperture. The annual calendar is displayed in three black edged windows at the top of the dial, with the power reserve indicator below the central date window. In keeping with the more relaxed aesthetic, the black hour and minute hands are luminescent treated. The mechanical self-winding movement, Calibre CH 28-520 IRM QA 24H, is visible through the sapphire case back, providing a power reserve of up to 45 hours, and is water resistant up to 30m.