Four years of Perpetual Calendar, included pictures of:
Vianney Halter Antide Janvier Perpetual Calendar | De Monaco Watch QP | De Bethune DB 15 Perpetual Calendar | Jules Audemars La Russe II QP | Lange & Söhne Datographe Perpetual Calendar | Lange & Söhne pocket watch n°28218 from 1889 | Lange & Söhne Tourbillon Perpetual Calendar
![[BaselWolrd 2011] De Bethune DB25 Quantième perpétuel](https://www.watchonista.com/sites/default/files/styles/body_content_722x0/public/watchographer/2914/albums/154679/pictures/baselwolrd_2011_de_bethune_db25_quantieme_perpetuel_square.jpg?itok=JBEvBiX6×tamp=1507841677)