WM-31

The WM-31 is a very plain playback Walkman built around the essentials: two AA batteries, manual tape selection, automatic shut-off, a flexible belt clip, and a simple plastic body with minimal controls. There is no Dolby, no reverse mechanism, and no tuner, leaving the player focused entirely on reliable cassette playback in a lightweight, low-cost form. It was built to be used without needing much explanation.

Much of the Walkman story was still being carried by extremely everyday machines. Not every useful model is useful because it was ambitious. The WM-31 was part of the baseline Sony had to keep stable while the rest of the lineup became more elaborate.