http://www.iwc.com/en/news/premiere-of-the-iwc-annual-calendar/
In 2015, the Year of the Portugieser, IWC’s newly developed annual calendar is another interesting additional feature to complement the perpetual calendar. The complication is powered by the new IWC-manufactured 52850 calibre. Both are found for the first time in the Portugieser Annual Calendar (Ref. 5035). The watch thus symbolizes the launch of an IWC initiative to produce further series of in-house calibre families in the years ahead.
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