The Montblanc 1858 watch series is inspired by the professional Minerva watches from the 1920s and 1930s which were conceived for military use and exploration. It combines a 42mm round shaped distressed stainless steel case and black leather strap with a traditional buckle. It has a black analogue dial with white luminescent rhodium-coated Arabic numerals and indexes, a date display, and two 24 hour sub-dials, all of which is protected beneath domed scratch resistant sapphire crystal glass with a double anti-reflective coating. Power is generated by the Calibre MB 29.25 automatic movement with 26 jewels and a power reserve of up to 42 hours. This model also has a water resistance of up to 100 metres. The Montblanc manufacture world-time complication is composed of two domed globes turning in opposite directions that complete a full rotation in 24 hours. Both are surrounded by a scale with the 24 time zones, along with a day and night indication in contrasting colours. This provides an instinctive way of appreciating the different time zones, aided by luminescent continents for increased visibility and performance at night.