Did you ever wonder what those cylinders on the cables near the connectors of many computer devices such as monitors, keyboards, and scanners? They are called Ferrite Beads or Ferrite Chokes. They reduce EMI (electromagnetic interference) and RFI (radio frequency interference) These eliminate interference between the oscillators of the mother board and these devices, for which cables can act as an antennae for. They are made of ferrite, an iron oxide alloy. As long as you don't try to remove them, they don't require your attention or affect how devices are connected.