This is Sony's portable cassette tape recorder "TCM-17". It's a model released around 1986 and runs on two AA batteries. It features recording and playback functions, fast forward and rewind functions, and speed control. Key features include: * Built-in speaker and flat microphone * Mono recording and playback * Operates on two AA batteries or an AC adapter * Showa retro design This model seems to have been a popular product that sold well at the time. I haven't been able to confirm its operation because I don't have a cassette tape.