I'm late to the party but now I had the chance to take a photo of my precious
I owned several "Stereo Cassette Players" in the 80s and later a portable Disc-Player. I never had the original Walkman. Then I was an early adopter when the music world changed to MP3 and immediately bought the Rio PMP300 when it became available here in 1999/2000. One of the first (or even the first?) hardware MP3 players.
I'm not a collector of anything and quickly get rid of stuff I don't need anymore (only regretted selling my Commodore 64...) but for some reason I kept the Rio and it rested unused for nearly 20 years since it was replaced by one of the first iPods.
I put a battery in ... and it worked right away! My songs from then still play (memories....), even the expansion card still works! Only the display looks strange but still readable.
This thing was such a gem for me as I was finally able to listen to music while running without skips and other problems you had with a discman or walkman.
It drives my Mentor plenty loud... and it sounds terrible