Physical Restraints are devices used for keeping people in a helpless state while in captivity.
Humans have traditionally used a multitude of restraints such as handcuffs and rope to keep individuals in restraint. The Neural-inhibitor collar is a UNSC device used to paralyze dangerous prisoners, and its practice has been used by United Rebel Front to subdue SPARTAN-IIs. Buckmesh is a particularly strong material used to contain prisoners of gangster Thin Kinkle, yet not strong enough on its own to stop a Spartan-I.
The Covenant has been known to use items such as shackles and contained beams of artificial gravity to hold prisoners. When Thel 'Vadam is tortured as punishment for letting Installation 04 come to destruction, he is kept restrained in a pair of hovering shackles apparently made of energy. A device containing a beam of artificial gravity is used to contain both 343 Guilty Spark and Professor Ellen Anders. While the Monitor floats motionlessly on its side, Anders is allowed some ability to wiggle within the confines of the gravity.