The Swatch Jelly Fish GK100, released in 1985, is a quartz watch in a transparent plastic case, with a see-through dial that exposes the movement and electronics. Like every early Swatch it is built from about 51 parts, with the case welded shut, and it has a plastic strap in a matching clear tint. I could not find reliable official figures for the case diameter of the original, so it is not stated here.

The Jelly Fish took the Swatch idea of watches as fashion accessories and made the mechanism itself the decoration. It is one of the best-known early designs from the line that rescued Swiss watchmaking in the 1980s.

Collectors seek the GK100 for its early date and clean look, and prices vary with condition, as clear plastic yellows over time. The original is long out of production.