The eXpanium is an MP3 CD player that uses a near-standard CD display, showing only track and album numbers and times, and has six transport control keys scattered over the lid. In addition to the usual functions, these provide 30 track programming, track and disc repeat and shuffle modes.

For Sony, the advent of MP3 must have been a particular irritation. After all, well before MP3 achieved any popularity Sony had released its own perceptual encoding/compression system for digital audio: ATRAC.