Swatch 'SKIN' analogue quartz wristwatch, 1998.

At the time of manufacture, the Swatch SKIN was the world's thinnest plastic watch, in a case just 3.9mm thick. Throughout watchmaking history, advances in technology and craftsmanship have led to the manufacture of ultra-thin or ultra-small watches. Responding to a Japanese wristwatch released by Seiko in 1978 which was 2.5mm thick, the Swis company ETA produced the thinnest watch yet made, the metal-cased 'Delirium IV' of 1980, at only 0.98mm thick. The SKIN is an affordable and practical version of the ultra-thin watch.