In the military, the watch is not a fashion accessory but a tactical tool that comes with useful features. Usually, these watches are large and bold and are designed to resist water, mud, dust, and shocks (among others).
Of course, these watches are not just for military personnel. They can also be used by outdoor adventurers, hikers, and people who usually activate in demanding environments. So, to satisfy this niche, Casio created the G-Shock series (starting with 1983).
These watches are indeed designed to withstand anything and everything. They keep going without a scratch where normal watches get ripped to pieces and many have amazing features that can be used in the field.
Their durability and reliability got so popular that today we have specifically designed Casio G Shock military watches for both men and women in combat.