Gangs
Unofficial groups, clans for walkmans
AM Stereo
Initially adopted by many commercial AM broadcasters in the mid to late 1980s, AM stereo broadcasting soon began to decline due to a lack of receivers (most "AM/FM stereo" radios only receive FM in stereo), a growing exodus of music broadcasters to FM, concentration of ownership of the few remaining stations in the hands of large corporations and the removal of music from AM stations in favour of news/talk or sports broadcasting. By 2001, most of the former AM stereo broadcasters were no longer stereo or had left the AM band entirely. (https://en.wikipedia.org/wiki/AM_stereo)
Dolby C
Dolby C noise reduction was a very common feature on mid to high-end cassette decks, not on portable devices. It further reduces background hiss, beyond Dolby B levels. To playback a Dolby C encoded recording, you need a device that can decode it for the best audio quality.
Glamour Boys
Glorious, glamorous, luxurious, and especially golden walkmans. The glamour boys have it all under control.
I'am so blockhead!
A little bit too rectangles?
Louder
Walkmans with built-in speaker, to spread the music wider!
Open else
Walkmans which doors opening differently, unusually.
Transparent
Just to be clear, do you see me? Transparent models.