The Zenith 40T is a manual wind watch movement that was used between the years 1972-1978. There are no known differences between the 2125, 2130, 2131, and 2132 models within this period. It should also be noted that the assignment of calibre names to the different versions of the AS/Durowe 1977 movement used in Dugena watches is unclear, as there are samples that display different versions, all carrying the Dugena signature.