What exactly is a Deluminator?

Question

“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.’ And you said… something about a wand….”

— Deathly Hallows, chapter 19, The Silver Doe

Ron and Dumbledore often used the device called Deluminator.

He had found what he was looking for in his inside pocket. It seemed to be a silver cigarette lighter. He flicked it open, held it up in the air and clicked it. The nearest street lamp went out with a little pop.

— Philosopher's Stone, chapter 1, The Boy Who Lived

How was it used, except for playing with lights?

Answer 1

From the Harry Potter wiki:

The Deluminator, also known as the Put-Outer, is a device used by Albus Dumbledore (the first known owner and designer of the one Deluminator known to exist) to remove light sources from the Deluminator's immediate surroundings, as well as bestow them.

In Deathly Hallows

It seemed to also act like a homing device. Whenever Hermione and Harry mentioned Ron's name, he could hear snippets of conversation before and after, even though he was far away. It then acted as a guide, leading Ron back to Harry and Hermione after he left them following an argument.

And:

In Harry Potter and the Deathly Hallows, Ron explains that the Deluminator creates a blue light which, after entering his chest near his heart, allows him to disapparate to where his love interest (Hermione) and his best friend (Harry) are located. The ability to transport a wizard, via a light through the heart, to where his or her favourite (or most treasured) people are is curiously similar to the epitaph Dumbledore selected for his mother and sister: "Where your treasure is, there will your heart be also."