Exactly what I was teling Goofy, Togo, except that you don't need to pay £99 for a pair. I was also telling him that you CAN buy them singly if you want to add to an existing pair and that the extras don't need to be the same brand as the air. I started with a pair and then added a third so tat I could attach a printer to the system.#
What is really important is that you need at least 2 - buying one, as he suggests, is like buying an extension lead with no plug on it.