H2TestW will test if the card is any good. It does not actually verify that it is a counterfeit. It only provides a good test to see if the card is working properly. You would still need to collect all the nearly microscopic letters and numbers on the card and call SanDIsk support to see if they can decode those numbers and match it up to being a valid SanDIsk product. As good as SanDisk may be, even a faulty genuine card would fail using H2TestW.
Having said all that, you really need to consider the source of where you are getting the card. If it is from eBay and the price is incredible it is most likely a counterfeit. I have bought 4 cards from various online sellers (eBay and Amazon Marketplace Sellers) and ALL were counterfeit. Fortunately, I was able to prove my case and got full refunds for all of them.
I have also been vigilant on checking out eBay auctions and getting the auctions closed when the user states something in the auction that indicates the card is counterfeit. For example, Kingston does not make a Class 6 32GB Micro SD card. If you see an auction for a Kingston Class 6 32GB Micro SD card, it is a counterfeit.
What I have seen in regards to these counterfeits is they appear to work initially. Thus people are willing to post positive feedback for the seller before the trouble begins. Sadly once the trouble begins, the buyer has already lost many pictures and files they thought were being captured and saved.
If you are still inclined to buy a Micro SD card off eBay or Amazon Marketplace, be sure to test it as soon as you get it with H2TestW and call the supposed maker of the card with the numbers. It has to pass both tests before you can feel safe that it is valid.
Amazon and Amazon Marketplace are different. A card bought from Amazon directly is probably going to be a good card. Amazon also allows individuals to sell items through Amazon and they are called Amazon Marketplace Sellers. Buying anything from a marketplace seller is very similar to buying that item off eBay.
