Harry Potter time turner necklace

Time-Turner was a magical device used for time travel. It was a special timepiece which resembled an hourglass on a necklace.[1][3] The British Ministry of Magic encased an Hour-Reversal Charm in the time turners they created, for additional stability. The number of times one turned the hourglass corresponded to the number of hours one travelled back in time. However, they could only stay in the past for five hours at a time, without the possibility of serious harm to the traveller or to time itself.[1] However, by 2020, two other "true" kind of time-turners were created. The prototype only let the time traveller stay in the past for five minutes, while the improved model let them to stay in the past for as long as they wanted, and return to the future when wanted.[5]