A touch of electric release button also cocks the shutter and advances the film The camera is thus always ready to take a picture.
1/10s - 1/100s shutter.
2.7/20mm lens, later 2/20mm.
(Source Princelle 2nd edition)
Images 2, 3 and 4 are from Detlev Vreisleben
Archives
Serial # 450189. Private collector.