“The Deluminator?” she asked, so surprised she forgot to look cold and fierce.

“It doesn’t just turn the lights on and off,” said Ron. “I don’t know how it works or why it happened then and not any other time, because I’ve been wanting to come back ever since I left. But I was listening to the radio really early on Christmas morning and I heard . . . I heard you.”

He was looking at Hermione.

“You heard me on the radio?” she asked incredulously.

“No, I heard you coming out of my pocket. Your voice,” he held up the Deluminator again, “came out of this.”

“And what exactly did I say?” asked Hermione, her tone somewhere between skepticism and curiosity.

“My name. ‘Ron.'”

Harry Potter and the Deathly Hallows – J.K. Rowling