Handcuffs are a type of restraining tool that can come in a variety of styles and materials. Materials include metal, leather, rope, silk, or silicone. Furry cuffs, which can introduce different textures to the play, are one of the popular styles. Cuffs can be used to link one or more limbs, either to each other or to furniture. Some varieties include locks that require a key to remove them, which also requires deep trust.