Handcuffs are metal devices to secure two wrists close together. Usually they have a ratchet-action to make them quicker to apply, and to make the size adjustable.

Plastic handcuffs, often known as flex-cuffs, are lightweight disposable plastic strips to immobilize individuals. They can be carried in large quantities by soldiers and police and are therefore well-suited for situations where many may be needed, as during large-scale protests. In recent years, airlines began to carry plastic handcuffs as a way to restrain disruptive passengers.

See also Bondage cuffs, Testicle cuffs