The fake will deceive you by displaying the 'false/oversize' capacity when you connect it to your PC, however they will NOT be able to store the data to the stated capacity. So you MUST perform data test by writing a BIG (1GB/2GB/4GB/8GB) file to the usb drive, then READ back the same file from the usb drive to another location on your PC to compare. The READ back process is the only proven way to uncover its 'REAL' capacity. A genuine USB flash drive will complete data transfer of a single 1GB file anywhere from 50 to 180 seconds writing to. Usually the writing time is twice as long as the reading time. The fake will take an excessively long time (1 to 7 hours) only 'pretending' writing but the data was not actually being written. Hence when you try to read it back, it will claim data as being CORRUPT. Many have reported that many strange files/folders eg. 00000.000 will appear and you cannot delete them. The fake flash drives are usually shipped out from ASIA especially from China, Hong Kong, Korea or Singapore, and they are also listed on Australian, UK, USA and European's eBay. The counterfeit model cannot be located or matched with any genuine models on the manufacturer's web site. Counterfeit 'USB Flash Drive / Compact Flash / Secure Digital / Memory Stick' are flooding the eBay market at very low Buy-It-Now (too good to be true) price to make you think is an absolute BARGAIN.