A Weapon modification is a device that alters the function of, or gives a new function to a weapon (specifically, a ranged one, such as a firearm). In Deus Ex: Invisible War, 8 varieties of these weapon "mods" appear, and at least one kind can be used on every weapon, barring melee ones. A maximum of two mods can be installed on any single weapon, and once it has been installed the player can neither remove it nor give it to another weapon.