This is a Sanyo Talk Book MicroCassette Voice Recorder TRC-570M.
This will work with MicroCassettes but not MiniCassettes.
it is used to record audio (e.g. dictation, lectures, notes, etc) onto a cassette which can then be played back at a later date.
The features of this item are:
Cassette format: Micro
Pause control - for effective editing
Twin speed - doubles tape time
VAS - Voice Active System