The 64GB card I purchased actually contains 4GB of flash memory and some kind of hack that causes it to appear as a 64GB drive in various drives and readers. Of course, this took me a while to figure out since I only just got around to copying more than 4GB of data to the card, but with some testing I have nonetheless discovered this to be the case.The card I bought was in Amazon Frustration Free packaging. I don't know if cards purchased that way are less likely to be counterfeit than retail packaged versions, but I suspect that I will stick with manufacturer packaging from now on.