WM-FX31

The WM-FX31 is a radio Walkman that built on Sony's low-end FX platform by adding auto-reverse playback while keeping the rest of the machine fairly restrained. It combined FM/AM reception, anti-rolling support, manual tape selection, and a simple upright plastic body with carry clip, giving it a feature set that was modest but noticeably more complete than the most stripped tuner models below it.

Auto-reverse is the whole story here. This is one of those models that suggests less because it was distinctive and more because it suggests certain conveniences had become everyday by the early 1990s.