Laptop charger cables on what is cylindrical object?

The keyboard and mouse cables are often in the cylinder which is neither a string nor any circuit.
Did you ever take your laptop charger is small cylinder reviewed in the end what it is or what the purpose of applying it? 

If they do not have the answer.

Often only a small cylinder laptop charger plus "keyboard" or "mouse" will hold the wire, but we must see that I have not opened it for what it eventually, so we points out that it is in the cylinder. So, neither the cylinder nor the wire a circuit, just two magnets are placed in the cylinder which control our attachment magnetic waves.
block and secure wire and electronic devices have to work.