Basically a four fingered ring. One of the best hand combat weapons ever invented. Used in the proper way can leave an opponent unconscious or possibly dead. They usually come in Brass, steel, Pewter, and copper.
In london they call brass knuckles Knuckle Dusters.
In Japan they call them Tekko with a slightlly different design.
These do not technically exist within the American Region no matter how hard people try to convince you they do. An "American ghetto" is very tame where they sell drugs some murders ect. A real ghetto has thousands of murders, houses made from trash, 3 legged dogs running wild and all of the above. Take a look at the slums of Kingston Jamaica, India, Pakistan, Iraq, South America, Mexico, and Russia! Stop trying to act so poor and ghetto you retards.