"Ballistic armor is manufactured from electrically sensitive polymer sheets that intrinsically react to the violent impact of a bullet or an explosion by 'stiffening' in response and absorbing the majority of the damage. These polymer sheets must be charged before use; after the charge has dissipated they lose their reflexive properties and should be discarded."
Ballistic Armor is the modern form of body armor in the 2050s, and one of the wearable items in Deus Ex.
Ballistic Armor uses the Environmental Training skill; at Untrained the suit will remain charged for several seconds. At Trained level, they will remain charged 50% longer than usual. At Advanced, they will last twice as long as usual, and at Master level, they last 4 times as long as usual.