Published by on August 18, 2026 The case back for this model features a 3D laser engraving of the K2 mountain that is depicted with incredible color, depth, and realism. Montblanc 1858 Geosphere 0 Oxygen 8000 Titanium Watch 42mm. 42mm titanium case without oxygen and with a fluted crown that features a Montblanc emblem in relief as well as a stainless steel and a fluted black ceramic bi-directional turning bezel with luminescent cardinal points.