To escape from the Death Star, Obi-Wan Kenobi needed to shut down the Tractor Beam. That is way you need this set.
This set is an extension of the Set 2a - Death Star Extension Bridge and Set 2b - Death Star Extension Bridge hallway. And can also be used in the Set 2 - Death Star Shaft
There are 3 versions of this set, one having the extension where Obi-Wan turns off the tractor beam.
1:6 https://www.cgtrader.com/3d-print-models/miniatures/sci-fi/set-2g-tractor-beam-power-generator-1-6-scale-hottoys
1:12 https://www.cgtrader.com/3d-print-models/miniatures/sci-fi/set-2g-tractor-beam-power-generator-1-12-scale-blackseries
1:18 https://www.cgtrader.com/3d-print-models/miniatures/sci-fi/set-2g-tractor-beam-power-generator-1-18-scale-hasbro-kenner