I got this card for my new low-end Android phone that I use for software and hardware testing. I just needed a basic SD card, and the 4 GB one was more than sufficient for most of my needs. It was easy to install, and more than adequate for all of my picture and video taking needs. I was able to use the included adapter to connect the card to my MacBook Air. When transferring files from the card to the computer the transfer speed was about 18 MB/s, while when uploading files to the card it was about 5 MB/s. So far the card has been reliable and I have not had any issues with corrupted or lost data.I really can't believe how cheap these cards have become. They are literally becoming too cheap to matter. 

Question: What is the function of the card?
Answer: I use for software and hardware testing