From Halopedia, the Halo wiki
When activated, the energy shackle emits a blue ring of energy around one of the limbs of an individual, and levitates in a fixed position, making it extremely difficult to move. The shackle also has the ability to electrocute the restrained individual.
In October 2552, a pair of energy shackles were used to restrain Thel 'Vadamee while he was branded with the Mark of Shame. Sali 'Nyon was bound by a set of energy shackles when he was captured by Jul 'Mdama's forces in July 2558.
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