Developed in antiquity, this weapon is nevertheless quite prevalent in the post-Great War wastelands.
Brass knuckles take the form of four linked metal rings in a shallow convex formation with a bumper attached to the concave face. The rings are slipped over a combatant's fingers with the bumper pressed into the palm of the hand. When a punch is thrown, the brass knuckles take the majority of the impact impulse, transferring much of the punch's kinetic energy to the target by way of the harder, smaller impacting surface of the metal knuckles. This drastically increases the likelihood of serious tissue disruption and bone damage.
In Fallout 2, peculiarly you can find spiked knuckles earlier than you can find this, making brass knuckles somewhat useless. However, light weight coupled with reasonable value means that players with adequate Barter skills can make a respectable profit looting these from fallen foes. As they are far more common than firearms in the lower levels, the collection and resale of brass knuckles can provide a much-needed early-game source of income.