Corum birthed its Bubble back in 2000, an aberration that eschewed the conventional wisdom of dial legibility in favour of a crazy crystal, so extremely convex that it changed the profile of the watch and distorted the dial.
Inspired by an experimental dive watch from the 1960s (almost certainly the Rolex Deep Sea Challenge Special that travelled to the very bottom of the ocean strapped to the hull of the Bathyscaphe Trieste in 1960) the Bubble has always been more of a fashion statement than a practical, tool watch.
As such the original run spawned all manner of limited edition runs with outlandish dial graphics. The 2015 Bubble is a much more sober affair (if a watch with an 8mm thick crystal can ever be considered sober) with two limited editions in black and bronze PVD as well as this series-run skeleton. This reborn modern classic has made a welcome return.