What Am I Riddles

Question: When you need me, you throw me away. But when you're done with me, you bring me back.

What am I?

Question: What fastens two people yet touches only one?

Question: Of the king I am blue and of the peasant I am red.Of the frog I am cold and of the dog I am hot instead.What am I?

Question: I'm many people's favorite place,
even though many don't remember their stay.
You'll love to come but hate to leave,
if you get cold use my sleeves.

What am I?

Question: There is an ancient invention still used in some parts of the world today that allows people to see through walls.What is it?