I was in a rush and picked up a new Pentium M 'centrino' laptop from Toshiba on Friday. Its an amazing laptop with a great screen. It came with a wierd device that they want to have attached to any cat5 cables hooked up to the network port. What is this device for? its about an inch long, goes around the cable, and obviously has some kind of metal (magnets) in it as it is very heavy for its size. Just curious what this is.