I just bought 2 16GB SDHC cards from a reputable dealer. The documentation with the cards and the cards themselves have them as SanDisk Ultra SDHC Card with Class 6 and 20MB/s.
The specs on the SanDisk product pages say that SanDisk Ultra SDHC are only Class 4 and 15MB/s.
Why is there a difference in the specifications? Is it possible I have bought a fake?