Sony launched the digital audio revolution in 1983 with the first compact disc player.
In 1984 they went one better, by introducing a miniaturised CD player that was so small and lightweight and sturdy that you could carry it with you.
The new D-5 portable CD player weighed in at 1lb 5oz and was about 5″ square and 1½ ” deep – only slightly larger than the compact disc itself.