Ever remember what we did pre iTunes when it came to getting and playing our music? Well one thing I remember doing was making up tapes sometimes 'mix tapes' with various tracks sometimes whole albums for playing back elsewhere.
This was one machine I had in high school for it as it was both a home stereo cassette recorder you used with your stereo unit and also a self contained mono player you could take away with you without any mains to play back your tapes on.
There were a great many different lengths of tape that offered different playing times per side of the dual sided cassette but generally I stuck to 60 and 90 minute lengths as they covered most needs and tended to be more reliable as longer tapes would be thin being more prone to wear or even jamming up. Cleaning up after a jammed tape in the unit wasn't funny!
That's what the tapes looked like , this one plays for forty-five minutes per side and is one of the higher quality type II sorts that I used a lot of back then although I started out using the cheaper regular type I TDK D ones as the really cheap tapes the drugstores stocked didn't sound so good and were not reliable.
That machine also had a stereo headphone socket so you could use like a 'Walkman' although Walkmen were smaller if no less chubbier to start with, more of use on the bus or train where space is at a premium.
I kept this until I got a proper Hifi deck and separate walkman in the early 80's