A ball and chain was a physical restraint device historically applied to prisoners, primarily in the British Empire and its former colonies, from the 17th century until as late as the mid-20th century. A type of shackle, the ball and chain is designed so that the weight of the iron ball at the end of the short chain restricts and limits the pace at which its wearer is able to move, making any attempt at escape much more difficult.
A ball and chain believed to date to the 17th century was found in the United Kingdom in 2009. It consists of a sphere of high-grade iron approximately 15 centimetres (5.9 in) across and weighing around 8 kilograms (18 lb). The chain is of some 90 centimetres (35 in) in length and terminates in a leg iron or shackle.