This is a two-way mirror. I’ve got the other. If you need to speak to me, just say my name into it; you’ll appear in my mirror and I’ll be able to talk in yours. James and I used to use them when we were in separate detentions.

And Harry’s heart began to race. He remembered seeing his dead parents in the Mirror of Erised four years ago. He was going to be able to talk to Sirius again, right now, he knew it —

He looked around to make sure there was nobody else there; the dormitory was quite empty. He looked back at the mirror, raised it in front of his face with trembling hands, and said, loudly and clearly, “Sirius.”