WM-31SS

The WM-31SS is a variation on the basic WM-31 that added a built-in stereo speaker system while keeping the same simple playback-only cassette platform underneath. It retains the two-AA power setup, manual tape selection, and straightforward plastic body, but the integrated speakers make the player usable without headphones when private listening is not necessary. The core transport remains unchanged.

This model also reflects Sony's habit of extending proven low-end platforms through compact but functional package variations instead of full redesigns. It was not a major branch in the Walkman story, but it shows how the company kept the format flexible for different everyday situations. It reads closer to a casual-use player than a personal-stereo purist one.