WM-F107

The WM-F107 was a solar-assisted Sports Walkman from 1986, with a large solar panel built into the lid to help charge its internal battery and support the radio and electronic functions in sunlight. The cassette transport still depended on stored battery power, but the sealed weather-resistant body also included auto-reverse, Dolby B, metal-tape support, and full AM/FM reception. Packing all of that into a Sports shell made it one of Sony's densest and most unusual portable designs of the decade.

This is a very Sony experiment: practical on paper, slightly eccentric in execution, and impossible to confuse with anything else in the lineup. It shows the Sports branch becoming not only a place for ruggedness, but also for technical experimentation around power and outdoor use. The F107 was never an ordinary mainstream player, but it is exactly the kind of model that makes the Walkman family feel inventive rather than merely iterative.