The Prisoner Immobilization Unit was a portable electronic device used to subdue and "brainwash" humanoid prisoners. The device fit over the head and shoulders of its victim.
The devices were used by the Galactic Empire. The Empire's Reconnaissance Troop Transporters were equipped with the units.
Leia wears an Immobilization Unit in trading card art
The Imperial troop transporter comic book that came packaged with Kenner's Imperial Troop Transporter toy erroneously used this device's name to refer to the Droid Prisoner Compartment, but the mistake was corrected later in the story. The original toy released in 1979 as part of the Star Wars toy line came with two of these units, as did the slightly modified and renamed "Imperial Cruiser" toy from Kenner's The Empire Strikes Back toy line.
A 2009 Topps Star Wars Galaxy Series 4 trading card featured art by Matt Busch portraying an "imaginary scenario" of stormtroopers traveling in a Troop Transporter having captured Princess Leia. The princess is shown wearing a Prisoner Immobilization Unit over her head. The design of the vehicle matches the toy design exactly.
