In BDSM, shackles refer specifically to metal ankle and wrist restraints, but can also be used for leather restraints in certain cases.
Shackles are typically made of metal and use a circle or U shape. They are usually linked together with chain to further restraint the submissive. Shackles are locked either through a padlock or with a bolt.
More About Shackles
Because of their price, shackles tend to be used only by experienced or professional dominants. They are a basic feature of BDSM dungeons.
Shackles are used in bondage play to restrain the subject’s movements. The weight of the shackles, added to the weight of the chains that link them together, further restrains the submissive. Many dominants and submissives also enjoy the sound of the chains.
Several configurations exist for shackles, from the typical ankle-to-ankle and wrist-to-wrist to the five-point shackles (collar, wrist and ankle restraints) as well as shackles chained to beds, benches, walls, cages and other dungeon furniture.
While shackles can be used as long-term restraints, wearing them for extended periods of time can cause damage to skin and even bones because of the friction from steel. A dominant should always make sure that the shackles fit properly and that wearing them will not harm the submissive.