Wuming,
Yeah it's very small (smaller than a pack of cigs), uses an external AC adapter that is also small. It looks as though it could be an accessory for an Apple iMac (very well designed asthetically!). You could easily hide it on your desk or in my case, it is mounted on the side of my desk next to my ethernet hub. Bought it at Fry's Electronics (it's regular price is $19.99 which is still a good price). And so far no problems with it.