HOW TO KNOWS THAT YOU BUY GENUINE APPLEiTOUCH / iPODPLAYER, not the fake one??

HOW TO KNOWS THAT YOU BUY GENUINE APPLE iTOUCH / iPODPLAYER, not the fake one?? The first thing very different is the price. imitation product price only 25% of the original one. Acceleration of data processing  of imitation product is very slow. Fake product is using low quality LCD screen ! Fake apple iPhone's camera is using VGA camera, which mean has low pixel image. The fake products has no 3G feature, apple application (iTune), etc.. Other points would be post later.. So, becarefull when you buy famous electronics brand these days..! www.apple-ipods.co.cc