What does Faber give to Montag, and how it it suppose to help him?

Faber gives Montag a Seashell radio. This radio will allow Faber to stay in contact with Montag, all while listening to and analyzing the firemen's world.

He picked up a small green-metal object no larger than a .22 bullet.
"I paid for all this-how? Playing the stock-market, of course, the last refuge in the world for the dangerous intellectual out of a job. Well, I played the market and built all this and I've waited. I've waited, trembling, half a lifetime for someone to speak to me. I dared speak to no one. That day in the park when we sat together, I knew that some day you might drop by, with fire or friendship, it was hard to guess. I've had this little item ready for months. But I almost let you go, I'm that afraid!"
"It looks like a Seashell radio."
"And something more! It listens! If you put it in your ear, Montag, I can sit comfortably home, warming my frightened bones, and hear and analyse the firemen's world, find its weaknesses, without danger. I'm the Queen Bee, safe in the hive. You will be the drone, the travelling ear.