J.L
My previous card was a Sandisk 32gb class 4 card. This card's speed is about 3x faster! Now I can put more music and movies to my hearts content! The only thing about this that I can say is a "negative" is that in order for my HTC Sensation 4g to recognize it, I had to reformat the card, even though the packaging says it's Android compatible. It even has the mighty green Andy the Android on it! LOL But after formatting the card in windows 7, I was able to use it in my phone. I didn't use the fat32 utilities so I cannot remark about those formatting procedures.Oh and I forgot to add the first card that was sent didn't work at all. The card didn't try to format. Amazon sent me one overnight without charge! Well I had to return the bad one of course, but the process couldn't be easier. The card was actually backordered a few weeks because of the deal of the day Amazon had on the card, which I purchased under as well...This card is authentic, came in Sandisk packaging and is indeed a CLASS 10 card.