Crystal Mirror

The Crystal Mirror is a magical mirror featured in the first two Equestria Girls films, IDW comics, software, and adaptations of the films and animated shorts. Twilight Sparkle, Sunset Shimmer, and Spike use the mirror to travel back and forth between Equestria and the human world.

In When the Cold Breeze Blows Away, it would be located in Equestria that it can made the Mane Six trying to travel to between Equestria and the human world.