Meet Corum Bubble (ref. L390/03639), a distinctive model that balances proportion, precision, and presence. On the wrist, the case feels purposeful: crafted in titanium and measuring 52 mm in diameter, with a thickness of 20.2 mm, defined by a round silhouette. The caseback is open, and the crystal is sapphire, delivering water resistance to 10000 meters. Visually, the face is where character emerges: a black tone, executed in brass, framed by stick / dot hour markers, and proprietary hands. Among collectors, it is nicknamed "Speaker". Mechanically, the watch prioritizes accuracy: the CO 390 caliber. Produced in limited numbers, appealing to focused collectors. Introduced in 2018. The silhouette offers presence without excess, lending confidence in a range of situations. Finishing showcases disciplined attention to detail across facets, edges, and surfaces. For buyers researching specifications and real-world impressions, this reference stands out for coherent design, dependable mechanics, and lasting relevance within modern horology.