A Russian flanger PE-11. We suggest this one was produced after 1990 since the labeling is in English. The units seems to be a successor of Elektronika FL-01 flanger made by the same factory in the early 80's.
One may wonder what "manual" control does. As far as we know, it brings a little LCD screen with instructions how to use the pedal and when you turn the knob, it scrolls the text. The absence of the footswitch is another trick - there's a little voice sensor you can see on the upper left part of the pedal, and when you scream "Flanger!!!" it turns the effect on and off. Unfortunately, the "manual" and voice control options were broken on this particular pedal, so we had to take our best guess.

Credits:
Tom