An ankle restraint is a piece of bondage gear used on the ankles to restrain movement of the feet and legs. It usually consists of two shackles or cuffs linked together by a rope, chain or bar.
More About Ankle Restraint
The types of restraints available range from vanilla velcro cuffs to dungeon-grade heavy iron shackles (and of course the ubiquitous leather cuff). They are available in locking and non-locking versions and typically come in pairs. Some restraints come simply as a pair of unlinked cuffs, leaving the user to find something to link the cuffs together, while others come as a set with a chain included.
Ankle restraints can be used to tie ankles to each other, to tie ankles to furniture, or even to tie ankles to wrists, as in a Hogtie position. A spreader bar will force a submissive's legs open and severely restrain movement, while rope or chain can be used to force the submissive to take small, short steps, adding humiliation to the scene.