Calibre 853 is an automatic watch movement from IWC in the 1950s.
IWC's main automatic movement for the 1950s, Cal. 852/8521, was updated around 1958 to become this Cal. 853. Once again, a date version was also available, Cal. 8531. Cal. 853 was replaced by Cal. 854 around 1963.
Like all previous automatic IWC movements, going back to the original Cal. 81, Cal. 853 features the patented Pellaton winding system.