Legcuffs

Legcuffs are physical restraints used on the ankles of a person to allow walking only with a restricted stride and to prevent running and effective physical resistance.

Frequently used alternative terms are leg cuffs, (leg/ankle) shackles, footcuffs, fetters or leg irons. The term "fetter" shares a root with the word "foot".

With respect to humans, shackles are typically used on prisoners and slaves. Leg shackles also are used for chain gangs to keep them together.

Metaphorically, a fetter may be anything that restricts or restrains in any way, hence the word "unfettered".

The earliest fetters found in archaeological excavations date from the prehistoric age and are mostly of the puzzle lock type. Fetters are also referenced in ancient times in the Bible.

Roman times already see a variety of restraint types. Some early versions of cup lock shackles can already be found. These were widely used in medieval times but their use declined when mass production made the manufacture of locks built into restraints affordable.

Simple fetter types continue to be used like puzzle lock shackles as the typical slave iron or irons riveted shut for prisoners being transported to overseas prison camps.

The first built-in locks often were of a simple screw-type but soon developed into the "Darby" type. In Europe these continued to be used into the middle of the 20th century, whereas in the U.S. from the late 19th century onwards many new designs were invented and produced before handcuffs and leg irons of the Peerless type became the standard several decades ago.

In comparison to handcuffs the wearing of leg irons may be found less restrictive. Thus the prison authorities in several countries deem their long-term use acceptable. In order to avoid condoning this disputed practice, the countries of the European Union have banned exporting leg irons into non-EU countries. The countries that continue to make prisoners wear fetters long term now tend to resort to manufacturing their own restraints.

...
Wikipedia