Time-Turners are magical time-traveling devices resembling an hourglass in the Harry Potter series that allow one to reverse time and travel backward. Hermione Granger was given a Time-Turner in Harry Potter and the Prisoner of Azkaban to attend more than one class simultaneously. However, these magical instruments can be used for much more than merely trying to stay caught up in schoolwork.
Source：https://www.cbr.com/heartbreaking-harry-potter-moments-time-turner-could-have-prevented/
