The Time Cube was developed by Rond Vidar, who was a genius with his research of time-travel and time-manipulation theory. At an early age, he developed the the device which could transport matter through the Timestream. The Time Cube proved indispensable to the Legion of Super-Heroes, who used it to stop Rond's father, Universo, from taking over the world.
The difference between the Legion's own Time Bubble machine and Rond's device is that the Bubble travels "through" time, while the Cube instantly transports its contents to the past or future. For the objects to return to their original era, they must be in the same spot which they arrived: also the maximum time a person can remain in the projected timezone is 24-hours. If they're not at the appointed spot then, they'll be stranded in that period.
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