My use for this item is to replace the 2GB card originally supplied with my trusty BlackBerry 9700 Bold Sim Free Mobile Phone - Charcoal
. It seems needless to say that it works perfectly, but I say it anyway. As is standard for SDHC cards, it comes formatted as FAT32, but is capable of being re-formatted if required. I popped the 2GB card into an adaptor, copied all the files to disc, and transferred them to the new card. Into the phone with it, and bingo, Bob's your uncle, perfect function.
Amazon's product description seems not to be very informative, so I'll expand on it.
SDHC = Secure Digital High Capacity. The cards have the Secure word in the title because they were designed to support DRM anti-piracy copy protection. That is a rarely-used feature, but it is possible for a device to lock the card so that it cannot be read in another device. Windows Phone 7 devices have the capacity to do that, and the purpose is obvious; groovy tunes downloaded to the card could not then be released into the wild as freebies. High Capacity is applied to cards with greater than 2GB, the limit for FAT16 with standard size file clusters.
Class 4 means the card supports a sustained write speed of 4MB per second. That is more than fast enough for the relatively low resolution video recording offered by phones, and in fact Class 2 (yes, 2MB per second) would be adequate. For HD video Class 6 is preferrable.
Make what you will of the card's protective features. I have many times passed flash cards through airport x-ray scanners, and never with adverse effects. But if you are the sort of clumsy oaf who commonly drops items into the toilet, then water-proofing has got to be a good idea. Similarly, if intense magnetic fields are the norm in your environment, then look no further.