Perpetual calendar in vitrophanie 60s

The perpetual calendar was considered in the 50s and 60s as the ideal medium for modern, attractive and unalterable advertising. Rare perpetual calendar in vitrophanie on plastic box for mallat, on the theme of architecture. Made by gerrer sa mulhouse. Date display by 4 side dials. Works very well. Slight mark of time on one side of the glass. Very good condition.