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KGB - Spy Cameras
This is the old soviet microfilming device "Корица" (cinnamon). It was used in libraries and document archives to archive the old documents on 16mm film (takes less space and could be keeped for longer time).
It was used of course for the secret services as well (mostly for microfilming of the secret technical drawings and drafts)
Uses standard perforated 16mm film.
Images source - eBay seller biggerby2002