WM-SR1

This 1999 model stood apart as a hybrid cassette Walkman with built-in stereo recording via an external microphone and a surprisingly powerful two-way speaker rated at 150 milliwatts. It includes an FM/AM tuner, Mega Bass, AVLS volume limiting, and a basic auto-stop mechanism without auto-reverse or Dolby. Two AA batteries powered the unit, and the slightly larger plastic body accommodated the speaker grille and recording input.

The SR1 occupied a niche between headphone-only players and compact portable stereos. Sony designed it for users who needed occasional recording or speaker playback in the field-campers, students, or hobbyists-while still keeping the familiar Walkman form factor, giving the late cassette lineup a functional utility option that most pure playback models lacked.