Dugena started as a German-Swiss watch company called Alpina, and moved to Glashütte in the 1900s. After the outbreak of war, the company was renamed Dugena - "Deutsche Uhrmacher-Genossenschaft Alpina". Diameter - 31mm.
The Dugena 4002 calibre is a re-brand of the Valjoux 7733 chronograph movement. This particular watch dates from the late 1970s/early 1980s.