The only heavy armour that isn't affiliated with any particular faction, it's become standard with mercenaries and wanderers.
Mercenary Plate is armour that is equipped in the Bodyarmor slot. It belongs to the Heavy Armor Class and is often seen worn by Shop Guards, Caravan Guards and Heavy Mercenaries. It offers nearly complete coverage against attacks on the chest and arms, but only partial coverage of the stomach. It can be obtained through Armour Traders or from crafting on the Heavy Armour Smithy.
"Good Quality Grade" versions can sometimes be looted from Dust Bandit Bosses, but cannot be crafted.
Mercenary Plate is built from several different pieces of armour plating. From the shoulders to mid-chest are heavily protected by pieces of armour plating designed with the appearance of muscles. The shoulders are protected by giant pauldrons. Wristguards held by leather bands cover the forearms and hands of the character. Despite all this, the armor leaves the stomach fairly exposed.