The iPod Nano And The Last Click Wheel
A tiny square with a clip, worn on a jumper.
The sixth-generation Nano dropped the click wheel for a touchscreen the size of a postage stamp, and people wore it as a watch.
Third-party watch straps for it sold in enormous numbers, which is broadly why the Apple Watch exists.
It was the end of the dedicated music player as a mainstream object. Phones took the job within two years.
Cost back then
£131
Goes for now
£60–£200