Typical set of Brass Knuckles.
Brass Knuckles were pieces of steel, aluminum, or copper metal shaped to fit around the knuckles of a human fist. They were the Special Weapon of Al Capone. They were designed to concentrate a punch's force to a smaller and harder contact area. Now they are illegal in such countries as Britain, Sweden, Austria, Germany, the Netherlands, Canada, and all 50 states of America.