If your card gets hot enough to be painful, it is defective and you need to contact SanDisk!From my experience, the larger micro SDs run hot on format and writing, but not to the pain threshold!I purchased one of these cards to use in a camera and Android tablet.  Great read speed but write speed was okay.  Used card for about two weeks and then all my files disappeared!  Tried to format the card and three different computers with XP, Windows, and Linux couldn't format it.  The camera and tablet couldn't format it.  I RMA'd it and got another because SanDisk is a good brand.  I did notice that when formatting or writing the card it got hot, very hot.Second card didn't last 24 hours and had the exact same symptoms as the first card.  Write a file or format it resulted in the card getting hot enough to reach the pain threshold.  I called up SanDisk and while explaining this was the second card I'd received with the exact same symptoms, when I mentioned it getting hot, they immediately issued me an RMA.  They said they were told to issue an RMA the moment they heard a card ran hot.Smaller SanDisk micro SD's or regular SD's I have or use don't do this.  I think SanDisk has an issue with this card.The last 4 digits of the part number refer to the date code and origin of the card.  Both cards had different date and origin codes.