WM-F104

The WM-F104 appears to be a misidentified or cross-referenced designation, most likely pointing back to the WM-104, one of Sony's cassette-sized miniaturized Walkman models with a five-band graphic equalizer and a more feature-heavy interpretation of the compact branch. That player combines auto-reverse, very compact-scale packaging, external battery support, and user-adjustable sound shaping in a body that pushes the mini format beyond simple playback. Some configurations also appear with Dolby B depending on market and source.

What it highlights is how messy Walkman model identification can become once regional documentation, catalog shorthand, and collector memory start overlapping. Even when a model name is uncertain, the underlying product logic remains visible. In this case, it points back toward Sony's attempt to make ultra-compact Walkman more customizable rather than just smaller.