Ever since I saw the "mobile phone music player" in Team Reptile's Bomb Rush Cyberfunk, I was intrigued by the idea of the player being given agency to chose their own music, should the default tracks playing in the level not come to their liking.
The WIPOD mp3 player functions similarly, allowing the user to find and cycle through music disks, possible future dev comentary entries, and most importantly - load their own music tracks and run them through the "My mix" cd.
Naturally, since the theme of the story is based on filth and soaps, the protagonist's music player is modeled after a wiper fluid bottle.
Lore-wise, I am thinking of there being a guerilla advert campaign, where some music store onwers set up boxes of disk players that allowed people to get a free sample of their wares. Now these boxes are broken and evicerated, ripe for the player to claim.