A Recall Tube is a transparent tube leading from Long Term Memory to Headquarters.
History
Its purposes are to suck memories to and from Long Term Memory. Emotions can recall certain memories and project them onto the view-screen, or the Mind Workers can send random memories (they favor the TripleDent Gum jingle) up the tube to project on the screen. Emotions can also send Memories down the tube. When a memory projects on the screen, Riley Andersen will remember it, and the emotions will view it. Joy and Sadness got lost through a Recall Tube when they got sucked up the tube in the process of Joy trying to stop a sad Core Memory being formed. Later Joy tries to go to Headquarters up a faulty one, and Fear tries to use one to quit, but it didn't work as emotions can't quit and there were memories in the way.