WM-F10

The WM-F10 took the extreme miniaturization of the WM-10 and extended it into the radio branch without giving up the core compact idea. Introduced in 1983, it added a manual FM stereo tuner to the same collapsible all-metal body, increasing thickness only slightly while keeping the single-AA power system, DC-DC converter, and Dolby B cassette playback. The headphone cable served as the radio antenna, and the tuning scale was integrated into the tiny body without overwhelming the design.

What makes the WM-F10 distinctive is its discipline. Sony could easily have let the radio section break the miniature logic of the WM-10 platform, but instead treated the tuner as something that had to obey the same philosophy of compression and restraint. Here, the engineering challenge is part of the appeal.